400-863-9100

Leysop Ltd.(英国)

http://www.leysop.com

地址:
18 Repton Court Repton Close Basildon, Essex, SS13 1LN United Kingdom
电话:
+44 1268 52 2111
传真:
+44 1268 52 2111
产品:
电光调制器  波片  Q开关  Q开关调制  偏振片  普克尔斯盒  光调制器  强度调制器  法拉第旋光器  法拉第隔离器 

公司简介

英国Leysop公司一家超过20年设计经验和制造经验的专业电光器件制造商。其产品包括电光Q开关、电光调制器及驱动、法拉第旋转器、光学偏振器、极化器与衰减器等全系列的产品。

Here you will find information on a wide range of electro optic and passive optical components such as Pockels cells, Q-switches, electro-optic phase and amplitude modulators, high quality calcite crystal polarisers, Faraday rotators and isolators and high voltage drive electronics such as Q-switch drivers and high voltage linear amplifiers for Pockels cell modulators.

Leysop are the only UK manufacturer of electro optic products and have served the international laser community with these vital products for over 20 years in total.

产品列表

Glan-Taylor Calcite Air Spaced Polarizer

Calcite Glan-Taylor polariser in mountThe Glan-Taylor design produces a high extinction ratio polarizer with low reflection losses and a high power handling capability. It is therefore particularly useful for polarizing laser light, with the further advantages that there is no transmission deviation or offset, and that a wide spectral range can be polarized.

Product Specification

POLARIZERGT10GT12GT15GT18GT20
APERTURE (mm)1012151820
WIDTH (mm)1113172022
HEIGHT (mm)1012151820
LENGTH (± 1.0mm)1115182124
TRANSMISSION RANGE------------------- 0.25 - 2.5µm -------------------
EXTINCTION RATIO10-510-510-510-610-6
TRANSMISSION UNCOATED----------------------- 88% -----------------------
MAXIMUM BEAM DEVIATION3 min3 min3 min2 min2 min
MAXIMUM OPTICAL POWER 
PULSED
------------------- 200MW/cm2 --------------------
MAXIMUM OPTICAL POWER
CW
-------------------- 300W/cm2 ---------------------

Diagram showing beam path through Glan-Taylor polarizer

LEYSOP supplies GT model Glan-Taylor polarizers with apertures from 10-20mm and larger to special order. Side faces are fine ground as standard, which is adequate to disperse the internally reflected polarization state. Polished side exit faces are provided if required and are recommended for all high power applications. The standard interface angle makes the polariser suitable for operation across a wide wavelength range. Other interface angles can be ordered to cover requirements across the full transmission range of calcite from 0.2 - 2.5µm. please note that because of the absorption in calcite, transmission for most Glan-Taylor polarizers is reduced below 350nm. The main optical surfaces are polished to a flatness of better than l/8 at 0.63µm. Please be aware though that side exit faces are not able to be polished to this same high specification because of the weakness of this face in calcite.Go to top of page

Glan Taylor Polarizer With
Orthogonal Output Side Exit Escape Windows

Glan-Taylor polariser with orthogonal side exit anglesBeam path through Glan-Taylor polarizer with orthogonal side exit angles

The Glan Taylor polarizer produces a high extinction ratio with low reflection losses and a high power handling capability. It is therefore particularly useful for polarising laser light. For some applications it is more convenient however to have the S and P polarized beams exit the device at 90° to each other. In this novel design, two specially angled side exit windows give orthogonal output escape beams and the mechanical mount gives a high degree of protection to all four optical surfaces. Another advantage of the angled side exit faces is that these are able to be polished to a much higher specification than the standard Glan-Taylor design.

Specification

PolarizerGLBS 10GLBS 12GLBS 16
Aperture10 mm112 mm15 mm
Spectral Range--------------- 350 - 2500nm ---------------
Extinction Ratio------------------- ³ 10-5 -------------------
Maximum Beam Deviation------------------- 3 min -------------------
Transmission--- 88% (uncoated) 93-95% (ar-coated) ---
Surface Flatness---------------- l/6 @ NaD ----------------
Maximum Optical Power-- 150W/cm2 (av) - 300MW/cm2 (pulsed) --
Overall Dimensions:
Height23 mm25 mm28 mm
Width24 mm27 mm30 mm
Length40 mm48 mm55 mm

Glan-Taylor Polarizer With Brewster Angled Faces

Glan-Taylor polarizer with Brewster cut faces

This special version of the Glan-Taylor polarizer is cut such that the P-polarization (extra-ordinary ray) intersects all four optical faces at Brewster's angle, thus ensuring a minimal insertion loss over a wide operating wavelength range. Transmission in fact is approaching 99% for the P-polarization and extinction ratio is exceptional, exceeding that of the more conventional cut Glan-Taylor.

One disadvantage of the Brewster cut Glan-Taylor polarizer, as you can see from the above diagram, is that it produces a reasonably large offset in the beam line. This is typically around 5 to 7mm depending on the size of the device and because of the refraction at the Brewster interfaces, it is also wavelength dependent.

Nominally available apertures are 8, 10 or 12mm and the polarizer can be supplied in a mount if required. As always, Leysop are happy to discuss your precise requirements for these and other components so please contact us.

Glan-Taylor Polarizing Beam Combiner

Glan-Taylor beam combining polarizer

Glan-Thompson Polarisers

Glan Thompson polarizer in cylinder mountCalcite Glan-Thompson cemented prism polarizers give the largest aperture field angle product of all calcite polarizer designs and the lowest transmission losses. The cemented interface of the Glan-Thompson however, prevents their use with high power lasers. Applications of the Glan-Thompson include spectral polarimetry and general light polarization and analysis investigations.

In the standard form the length aperture ratio of L/A = 2.5 gives a useable angular polarised field symmetrical about the prism axis of greater than 14° while the long form L/A = achieves over 25°. For UV applications, it is advisable to use the shorter aspect ratio devices because the additional losses caused by the greater thickness of calcite are too high otherwise to be useful much below 400nm

Diagram of Glan-Thompson polariserMounted Glan-Thompson polariser
Glan Thompson PolariserEnd View Mounted

SPECIFICATIONS

Spectral Range250 - 2300nm
Extinction Ratio> 105
Beam Deviation< 2.0 min
Transmission AR Coated97%
Surface Flatnessl/8
Max Power cw1.0w/cm2


TypeClear Aperture
(mm)
Ratio
L/A
Mount
Dia (mm)
Mount
Length (nm)
GTM 10102.52528
GTM 12122.52533
GTM 15152.53040
GTM 20202.54055
GTML 10103.02535
GTML 12123.02540
GTML 15153.03050
GTML 20203.04065

Rochon & Wollaston Polarisers

The Wollaston and Rochon polarizers are both beam splitting type devices which rely upon the large birefringence of calcite to cause a difference in the refraction angle at the interface between two differently orientated prisms. In both the Wollaston and the Rochon polarizer the prisms are usually cemented at the interface so the optical power handling is low as a result.

WOLLASTON TYPE

Wollaston prism polarizing beam splitters consist of two equal angle calcite prisms optically coupled with optic axis orthogonally crossed to the direction of propogation. The beam separation of about 20° is then approximately balanced about the input beam axis. The transmission range for cemented prisms of 0.32 to 2.5µm to 18° at 2.5µm.

ROCHON TYPE

In the Rochon polarizer one polarization state is transmitted undeviated through the prism while the orthogonal component is deviated approximately 10°. The straight through component is clearly chromatic while the deviated beam varies from 11° at 0.32µm to 8.5° at 2.5µm.

Diagram of Wollaston polariserDiagram of Rochon polariser
Wollaston Type BSWRochon Type BSR

Specifications

TypeAperture
(mm)
Deviation
(deg)
Mount
Dia (mm)
Mount
Length (mm)
BSW1020°2511
BSW1220°2513
BSW1520°3016
BSW2020°4020
BSR1010°2511
BSR1210°2513
BSR1510°3016
BSR2010°4020

Both varieties can be made from optically contacted quartz. The beam deviation is then reduced to only 1° and 0.5° respectively because of the much lower birefringence of quartz compared to calcite. However, the spectral range is increased to 0.2 - 2.0µm.

Beam Displacement Rhombs

This simple device, usually manufactured in calcite, provides an elegant way of separating a beam into its two orthogonal polarization components. A beam entering a block of calcite with its input and output faces cut at 42° to the optic-axis will undergo a maximum displacement (but not angular deviation) of the extra-ordinary ray component. The effect provides a displacement of the centroid of the beam of a little over 1 part in 10 of the propagation length, thus at 1µm wavelength the displacement produced by a 10mm long rhomb will be approximately 1.05mm. Other birefringent materials may also be of use for wavelengths not covered by the transmission of calcite, an example of which would be quartz, but the displacement produced will in general be lower than that of an equivalently long calcite rhomb because of the lower birefringence of quartz.

Beam displacement rhomb, available in quartz, calcite etc.

Specifications

ModelAperture
(mm)
Length
(mm)
Displacement
(mm)
Mount
Dia (mm)
BSC-08-20820225
BSC-08-30830325
BSC-08-40840425
BSC-08-50850525
BSC-08-60860625
BSC-10-201020225
BSC-10-301030325
BSC-10-401040425
BSC-10-501050525
BSC-10-601060625

Availability

Leysop can provide these components in other apertures and displacements as you require and with or without AR coatings, as you prefer. Components can be provided mounted in protective rings or supplied bare. Please enquire with us for your specific requirements and provided it is possible we would be happy to meet your needs. For example, a 5mm aperture rhomb of length 25mm (nominal displacement 2.5mm), AR coated for 532nm and in a mount would be specified as BSC-05-25-AR532-M

High Power Attenuator Using Glan Taylor Polarisers

Basic high power laser attenuator using calcite Glan-Taylor polarisers


Variable attenuators are frequently configured using a combination of a half wave retardation plate and a linear polarizer. Light is input through the retardation plate, a rotation of which produces a rotation in the angle of the plane of polarization as seen entering the polarizer. By Malus' law, the relative transmission of this combination (ignoring other loss mechanisms) is given by the square of the cosine of the relative angle between the plane of the input polarization state and that of the transmission state of the polarizer. This approach relies on the input light being in a well defined linear polarized state and the maximum attenuation will be dictated by the purity of the input polarization state. It is also wavelength dependent by definition as it relies on the retardation plate providing a half wave retardation which of course it will do only for certain wavelengths

This alternative design of optical attenuator uses a pair of high quality Glan-Taylor polarizers and therefore can be used at a choice of wavelengths between 0.35-2.0µm (subject to variations in transmission of the AR coatings). Maximum continuous rating is 200W/cm2 and peak power handling is up to 500MW/cm2 for q-switched pulses (1064nm). If the attenuator is used with plane polarised light the maximum transmission is ~90% and with unpolarised light the maximum transmission is ~40% (lower if un-coated prisms are used for maximum transmission uniformity).

The input polariser is rotated through up to 90o and energy in the side exit beam is dumped onto a light absorbing block. If required the block can be removed and the side exit beam allowed to leave the attenuator. The output polarization state remains fixed for any degree of attenuation as only the input polarizer rotates.

The design of this device has been updated to make it more compact than the original design and also to make it compatible with the popular 30mm cage systems, available from several manufacturers. This also allows for a greater precision in the readout of the rotation angle at which the variable Glan-Taylor polarizer is set. Another benefit of this change is that we can now offer a version with a precision, micrometer driven adjustment of the rotation (in addition to the quick adjustment) that allows for much finer control over the rotation setting, required for obtaining the maximum possible extinction setting. This version is shown below whilst the basic version is shown at the top of the page.

Precision high power laser attenuator using calcite Glan-Taylor polarisers

Specification

Dimensions (see Interface Diagram)
MountingM4 threaded hole / 30mm Cage System
Apertures Available10, 12 or 15mm
Maximum Continuous Rating200W/cm2 *
Maximum Peak Power500MW/cm2 *
Operating Range0.35 - 2.0µm *
Attenuation Range0.4 - 60dB
Beam Deviation<3 minutes of arc
Wavefront Distortion<1/4
Input Polarisation StateAny
Output PolarisationPlane Polarised

Faraday Optical Isolators

FOI 5/57 Faraday isolator FOI 5/711 Faraday isolator



TypeFOI 5/57FOI 5/711
Aperture (mm)55
Wavelength (mm)500 - 900900 - 1100
Isolation (db)³ 30³ 30
Insertion Loss (dB)£ 0.5£ 0.5
TunableThree Ranges
500 - 750, 750 - 850 and 800-900

±5° rotation about 
fixed wavelength
Dimensions (mm)
Excluding Polarisers60 dia x 58 long
75 dia x 75 long
With Polarisers60 dia x 100 long
75 dia x 120 long

In addition to the above 5mm aperture units, we are also able to supply 8mm aperture alternatives (e.g. FOI 8/57 and FOI 8/711) on request. Please be aware though that the cost of the larger TGG rods is disproportionally higher for this small increase in diameter and that larger and heavier magnets are also required. The cost of these rotators/isolators are thus somewhat higher than the smaller aperture models.


Low Order Quartz Retardation Plates

Diagram showing mounted quartz retardation plate

These retardation plates use high optical damage threshold crystal quartz. They are orientated with the optic axis in the plane of the plate and light polarised at 45° to the quartz optic axis is resolved into two equal amplitude components that suffer a relative phase retardation due to their different propogating velocities. Most low orderplates lie in a thickness range of 100-200µm (At 1.06µm a first order l/2 plate is aproximately 182 µm thick). Low order plates are generally used because they are relatively temperature insensitive compared to high multiple order plates. They are also less sensitive to axial misalignment.

Retardation plates can be supplied mounted or unmounted with or without A.R. coatings.

Specifications

MaterialCrystal Quartz

Surface Quality

20 - 10
Diameter Tolerance+ 0.00mm - 0.1mm
Retardation Tolerancel/250
Damage Threshold³ 1 GW/cm2nanosecond
pulse length at 1064 nm
Max cw Poweer³200W/cm2
Transmission Uncoated92%
Spectral Range220 - 2800 nm

Standard Sizes

TypeClear ApertureMount Dia.

QWP 10

10mm

25mm
QWP 2020mm25mm
QWP 2525mm35mm
QWP 3030mm40mm

Low order Half and Quarter wave plates having the above dimensions are held in stock and can be supplied coated or uncoated. They are generally available from stock for most common laser wavelengths. All waveplates can be supplied mounted or unmounted. Other dimensions can also be supplied.

Optical Depolarizer Plates

Just as important for many applications as having a well polarized source, it is sometimes necessary to ensure that a source is completely free of any preferred plane of polarization. An example of this is a sensitive spectrometer where varying degrees of polarization will lead to measurement errors. Of course, in nature almost all sources exhibit some degree of polarization, even thermal sources become polarized after reflection from a dielectric surface. Depolarizers are therefore essential items to have wherever a completely un-polarized source must be used.There are two principle methods of producing a depolarization but they operate in different manners and it is essential that the correct type is chosen based on whether the source is mono- or poly-chromatic.

Leysop can provide both types of depolarizer and these are described here.

Lyot Depolarizer

The Lyot depolarizer is assembled from two or more plates of birefringent material, in each plate the optic axis of the crystal lies in the plane of the plate and is orientated at 45° to the axis of the previous plate. The plates are manufactured in a geometric sequence of thicknesses, each plate being twice the thickness of the next thinnest plate. In the simplest case of two plates, one is just twice the thickness of the other. A three plate Lyot depolarizer requires one plate of thickness "t", one of thickness "2.t" and one of thickness "4.t". Depolarization is obtained through the production of varying amounts of circular and elliptical polarization states at different wavelengths. The depolarization effect is poor for monochromatic light as even with a large number of plates in the stack there are only a limited number of polarization states produced. By contrast, a polychromatic source will produce an effectively infinite number of polarization states and thus depolarization is strong, even with just two plates.

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Lyot depolarizers can be manufactured in just about any birefringent material, but most applications are covered by either quartz or calcite. Quartz is particularly suitable for applications extending into the ultra-violet and we can provide optically contacted components for minimum insertion loss. For applications where calcite is more suitable, we can provide either cemented or even air spaced components (but calcite is not suitable for optical contacting).

Wedge Depolarizer

The wedge depolarizer is the alternative form which should be used for monochromatic light sources. Again, a thick plate is manufactured in which the optical axis is in the plane of the plate. In use, the optical axis is aligned at 45° to the axis of the incoming polarized light and the thickness of the plate is varied in the plane of the incoming light (a wedge), thus producing a variable birefringence across the aperture of the plate. A second plate of index matching but non-birefringent material is added to the first plate to provide a compensation of the wedge angle, thus minimizing deviation of the beam but maintaining the depolarization. The most common combination is to use crystal quartz and fused silica, usually optically contacted together to enable applications into the ultra-violet.

Quartz-Silica Wedge depolarizer.

Availability

Leysop can provide these components in whatever diameter, thickness, number of sections you require (we have manufactured 22 section Lyot depolarizers for one especially critical application) and with or without AR coatings, as you prefer. Components can be provided mounted in protective rings or supplied bare. Please enquire with us for your specific requirements and provided it is possible we would be happy to meet your needs.

Savart Plates

The Savart plate is an extremely useful device, usually manufactured in either calcite or quartz, which is used for the detection of very weakly polarized light for example in starlight.

The beam displacement produced by the savart plate is approximately 0.075 times the total thickness in calcite and 0.0042 times in quartz. When ordering a Savart plate we need to know the material, aperture and thickness required, as well as if AR coatings and a mount are required. For example, a calcite savart plate of aperture 10mm and total thickness 15mm in a mount would be CSP10-15-M. The same part with single layer MgF2 coatings on the outer surfaces centred at 550nm would be CSP10-15-AR550-M.

ModelMaterialModelMaterialAperture
(mm)
CSP10CalciteQSP10Quartz10
CSP15CalciteQSP15Quartz15
CSP20CalciteQSP20Quartz20
CSP25CalciteQSP25Quartz25
CSP40CalciteQSP40Quartz40
CSP50CalciteQSP50Quartz50

Pockels Cells

Below you will see the variety of different types of longitudinal and transverse Pockels cells manufactured by Leysop for modulation, Q-switching, pulse slicing and pulse picking. If you don't see anything which meets your needs, give us a call. Custom devices are our forté.

Click on the image links for more detail.

Ultra-compact Pockels cell with integrated polarizer and waveplate for Q-switching.

NEW - Ultra-Compact Integrated Pockels Cells

For systems where a large aperture is required but the smallest Pockels cell must be used, the convenience of our new EM508UC is unbeatable. It combines a pre-aligned quarter wave retardation plate and a thin film Brewster plate polarizer for simple operation.




ultra-miniature longitudinal KD*P Pockels cell for electro-optic Q-switching

Ultra-Miniature Pockels Cells

This is our next smallest longitudinal mode KD*P Pockels cell, particularly suited to OEM laser manufacture. Aperture is presently limited to 8 or 10mm. Cells are supplied dry with AR coating for maximum optical power handling and are offered for the wavelength range 1047-1064nm. Stud or pin connections are available.




BBO Pockels cell for high power and repetition rate Q-switching and pulse picking.

High Power BBO Pockels Cells

Capable of operating at average powers of even hundreds of watts, for applications at the highest average powers there is no better choice than a BBO Pockels cell. The low piezo-electric coefficient also makes it suitable for high repetition rate applications.



RTP Pockels cell for high repetition rate Q-switching and pulse picking.

RTP Pockels Cells for High Repetition Rate Applications

This is our Pockels cell designed specifically for high repetition rate Q-switching and pulse picking (even to MHz rates) using RTP, selected for its complete absence of measurable piezo-electric resonances. Supplied as an OEM format cell in an industry standard package, a 100kHz driver is also available



longitudinal KD*P Pockels cell for electro-optic modulation and Q-switching

Standard Pockels Cells

This is our conventional range of longitudinal mode KD*P Pockels cells, particularly suited to general laboratory and darkroom environments. Apertures range from 8mm to 20mm and cells can be configured with either 1, 2 or 4 terminals depending on your interconnection requirements. Cells can be supplied fluid filled for low loss or dry for the highest optical power handling

Compact longitudinal Pockels cell for OEM Q-switching


Compact Pockels Cells

This is our more compact range of Pockels cells where a smaller size and simpler interconnect make them especially suited to OEM laser equipment manufacture. Both 8mm and 10mm aperture versions are currently available, but any aperture may be accomodated by this general style of packaging.

Ultra fast Pockels cell for pulse slicing and pulse picking

Ultra Fast Pockels Cells

This is our special range of ultra fast response KD*P Pockels cells, designed to give the fastest possible rise-times and cleanest responses for the most demanding pulse slicing and pulse picking applications. The aperture is a very useful 6mm diameter, large enough to accomodate most beams whilst being small enough to retain a 150ps time response.


Double crystal Pockels cell for reduced drive voltage

Double Pockels Cells

Double Pockels cells provide an excellent way of halving the drive voltage required by using two crystals to share the work. As well as being available in our conventional Pockels cell packaging, we can also provide compact style devices as well as ultra-fast versions.



three electrode Pockels cell for pulse slicing

Three Electrode Pockels Cells

For some special applications such as pulse picking and pulse slicing, there are advantages to using Pockels cell cells with three electrodes. These are effectively back-to-back Pockels cells which can then be driven independently to turn on and off the transmission of the optical beam with great precision and flexibility.

transverse field Pockels cells for electro-optic modulation and Q-switchng

Transverse Field Pockels Cells

With the exception of the RTP and BBO cells, all the above Pockels cells use KD*P crystals in longitudinal field mode. Whilst extremely effective devices, there are some applications where transverse field devices are superior choices. These are particularly so where wavelengths are longer than 1100nm, or where small size or low voltage operation are required. Most transverse Pockels cells are made using either lithium niobate or lithium tantalate, both materials of excellent optical quality. The optimum choice will depend on your application, so give us a call to discuss your needs. Custom requirements easily accomodated.

Low Voltage Electro-Optic Light Modulators
Type: EM 200A, EM 200K & EM 200L


EM200 low voltage elctro-optic modulator

EM 200A

This is a low voltage ADP transverse modulator designed to operate at all wavelengths in the visible and is entirely free from piezo-electric resonances. This modulator has a high degree of temperature stability, but where long term d.c. amplitude is required it should be operated in a constant temperature environment. The modulation frequency is not limited by the device characteristics other than by its electrical capacitance and therfore depends on the drive circuit used. Wide band ar-coatings are used on all components.

EM 200K

This is a low voltage transverse KD*P electro-optic modulator designed to give maximum thermal stability beyond that obtained by the ADP type. Its transmission range is extended into the infra-red and its extinction ration is also better than that obtained from its ADP counterpart. It does however display piezo-electric characteristics.

EM 200L

This is a low voltage transverse electro-optic modulator using high damage threshold lithium niobate. It has similar characteristics to the EM 200K with an optical range extended further into the infra-red.

Product Specification

Model No.EM 200AEM 200KEM 200L
Crystal TypeADPKD*PLiNb03
Aperture2.2mm2.2mm2.2mm
Crystal Length4 x 20mm2 x 40mm2 x 20mm
Half Wave Voltage at 633nm220V220V220V
Crystal Orientation45°y-cut45°z-cutz-cut
Wavelength Range0.3 - 1.0µm0.2 - 1.2µm0.5 - 4.0µm
WindowsBK7BK7Quartz
Max. Continuous Applied Voltage250250400
Extinction ratio³ 100:1³ 200:1³ 200:1
Capacitance60pf40pf60pf
Cell Diameter40mm40mm40mm
Cell Length110mm110mm110mm
Optical Transmission> 85%> 90%> 90%
Connectors---BNC---

All modulators are supplied Dry Nitrogen Filled.
Download the Interface Drawing

Download Interface Drawing

Electro Optic Phase Modulators

Resonant electro-optic phase modulator

Resonant Phase Modulator: PM50-100 (50 MHz to 100 MHz versions available)

By making the electro-optic crystal part of a tuned circuit, relatively low drive voltages can be used to achieve up to p radians of phase modulation. For the range 50 MHz to 100 MHz the enhancement of the voltage which is able to be applied across the crystal as a result is typically around 10 times that of the 50 ohm input drive.

For the tuned circuit arrangements the drive power required from the source is usually less than one watt.

These phase modulators can currently only be supplied without a drive source.

Outline drawing of phase modulator head
Outline Drawing of Phase 
Modulator Head


Optical wavelength range600 - 1300 nm
(Lithium Tantalate)
Crystal ConfigurationBrewster cut or
ar/ar normal incidence rod
Aperture2mm
RF Drive power2 watt maximum for p radians
Tuning range of optical head± 15% of centre frequency
Voltage gain from tuned circuit» 10
Input impedance of head» 50 W
Note: These are typical specifications taken from a 
phase modulator operating at 70 MHz.

Go to top of page

Travelling Wave Broad-Band Phase Modulator: PM1000 (up to 1GHz available)

For frequencies higher than ~100Mhz, we have found that the enhancement in voltage available from using a resonant circuit is soon lessened to the extent that it is not so effective. We then find that a more conventional modulator is beneficial, however we use a pseudo-travelling wave arrangement to provide a 50 ohm characteristic impedance and also some matching of the optical and electrical phase velocity to maximize the bandwidth. Using this arrangment we have made phase modulators with useful response to ~1GHz. The reasonable availability of moderately high powered (50W) r.f. amplifiers up to this frequency makes it possible to provide a voltage swing of around 140V peak to peak across the crystal which is sufficient to provide a sufficient degree of modulation depth for most applications. The device is supplied without driver or load (the r.f. signal must be terninated in a suitably specified r.f. load)

Microwave resonant phase modulator


Optical Wavelength range600 - 1300 nm
Lithium Tantalate
200 - 600 nm (ADP)
Aperture1.5mm typical
Characteristic design impedance» 50W
Drive PowerUp to 50 watts

Electro-Optic Deflector Q-Switch

Electro-optic deflector Q-switch and driver

The electro-optic deflector makes an ideal Q-switch for compact, low average power systems. Polarisers are not required and the optical loss can be kept to below 1%. The ability to deflect in a few nanoseconds allows short Q-switch pulses to be produced and high repetition rates obtained. The 1 mm aperture deflector has been successfully used to Q-switch a micro-chip laser at 20kHz while producing 1.5 ns pulse lengths. Leysop can supply the deflector with a miniaturised 1kV driver operating between 0 - 20 kHz. The Q-switch is not liquid filled and does not require accurate alignment.

Deflector Specification

Aperture1mm2mm3mm
Deflector length11m20mm25mm
Deflection angle for 1kV drive5mrad3mrad1.5mrad
Optical loss ar/ar at 1.06mm< 1%< 1%< 1%
Dimensions (mm, excluding connections)25 x 25 x 1120 x 20 x 3120 x 20 x 31
ConnectorSMASMASMA
Capacitance50pF50pF50pF
Switching SpeedDriver limitedDriver limitedDriver limited

Solid State 20kHz Driver Specification

Power Input+9V or +12V @ 0.7A D.C.
Output+900V pulse
Nominal Pulse Length20 - 100ns, internally adjustable
Rise Time into 50pF Capacitor£10ns
Trigger Input2 - 5V with 10ns rise time into 50W
Repetition Rate0 - 20kHz
Dimensions60 x 60 x 110mm
Connectors: Output & Trig. inSMA
Cable length between Pulser and Deflector500mm max.

250 Series High Voltage Video Amplifier

High voltage video amplifier for driving electro-optic modulators

This is a linear Class A output video amplifier with a maximum differential output of 275V over the range d.c. to 7MHz. The two outputs can also be set to ±250V dc relative to each other using a bias control. This facility allows an electro-optic amplitude modulator to be set to any desired light output intensity level for any input signal level. This output bias does not introduce any limit to the signal output range.

The amplifier has been designed to drive electro-optic modulators from the EM200 range where the load is purely capacitive and does not exceed 100pf. The output is short circuit proof.

Specifications

Signal output voltage range275Vdc - 6MHz bandwidth
Amplifier Square Wave Rise & Fall Time 
using 100pf load
< 65 ns (10% - 90%)
Bias Voltage Range+250V to -250V
Input Voltage for Full Output±1Vdc or 2Vpp., ac
Input Impedance50 W nominal
Cabinet Size (mm)Height 220, Width 530, Length 340
Mains Voltage110/200/240ac 50-60Hz
Temperature Range0° - 40°C ambient

5000 Series High Voltage Linear Differential Amplifier

Very high voltage linear amplifier for driving Pockels cells

This 5000V series linear amplifier has been designed to drive large aperture electro optic modulators. It consists of two 0.4 - 3.0 kV linear amplifiers that together produce a differential output that can be connected to either side of the modulator. This produces an optical phase change equivalent to the output from a single sided 5000V unit.

The amplifier has a bandwidth of 14KHz and a rise time of less than 5µs.

It incorporates a 1 - 10KHz internal oscillator giving sinusoidal, triangular and square waveforms. For square wave modulation applications the positive and negative excursions of the square wave output can be precisely controlled. This differential drive technique increases the lifetime of the modulator by maintaining a zero mean voltage across its terminals.

Specifications


Output Voltage Range400 - 3000V (each side)
Full amplitude Frequency Response14 KHz
Small Signal Frequency Response
(10% Full Amplitude)
100KHz
Rise and Fall Time5µsec
Signal-Noise Ratio50dB
Input Voltage-2.5V to + 2.5V
Input Impedance1000W
Cabinet Size (mm)220 (height), 530 (width), 340 (length)
Mains Voltage110/200/240ac 50-60Hz


HVP50/80 High Voltage Pockels Cell Q-Switch Driver

High voltage step pulse generator for Q-switching of Pockels cells

Step Pulse GeneratorHVP 50/80
Output Pulse
Voltage Range1 - 8 kV
Maximum Output current200 A
Electrical Falltime< 3 ns
Recovery Time100 µs exponential
Output Impedance50 W
Maximum on time at maximum
current
200 ns
Maximum Repitition rate100Hz
Minimum Pulse Width10 ns
External Trigger Input
Amplitude-3 V to + 3 V
Polarity of Leading EdgePositive or Negative
Input Impedance50 ohm
Minimum Internal Delay40 ns
Sync Output
Amplitude³ 3 V into 50 ohms
Jitter wrt High Voltage Pulse100 ps
Internal Rate Generator
Repetition Rate0.1 Hz - 100 Hz
Pulse Terminating Load
(designed to correctly terminate a 50 ohm coaxial cable)
AC Impedance50 ohms nominal
Cabinet
Volume (W x D x H)330 x 330 x 100 mm
Weight4 kg
Environmental Temperature
Range0°C - 40°°C
Supply
Mains Voltage @ 50 or 60 Hz120 or 240 V ± 10%
Power50W
Enable Input
Removal of a short circuit will prevent operation

100kHz RTP Pockels cell Q-switch Driver

High repetition rate Q-switch driver for RTP Pockels cells

One of the most difficult aspects in dealing with electro-optic devices is the problem of working with high voltages. The majority of electro-optic devices present a capacitive load to the driver which further compounds the problem of finding a suitable driver. However, the relatively low voltage requirements of the transverse field RTP Pockels cell allow us to switch the high voltage at high repetition rates with acceptable power consumption at the driver.

We have developed the driver with the application of continuously pumped sources in mind (rather than flash-lamp pumped for example). For this reason we have not incorporated any facility for varying the delay from the input trigger pulse and the Q-switch output pulse. We have however provided full protection facilities based on internal current limiting to ensure that the demands on the internal HT power supply do not exceed its capability. There is also an internal rate generator for those applications where synchronization to external events is not required and free running use is acceptable.

Safety is of course also paramount and the high voltage output is provided by a safe high voltage (SHV) form of the BNC connector and a matching lead is supplied to connect to the Pockels cell terminals. The HT votage may be set precisely from the front panel to enable the unit to be set for optimum performance at the user's operating wavelength and to allow for the different voltage requirement of the three aperture options available.

Provisional Specification

ParameterValue
Repetition Rate0 to 100kHz in five decade steps by internal or external generator
Output Voltage+200 to +2,000V adjustable with visual display
Output PulseThe standard system generates a positive going step function above zero. The generator can also be supplied giving a negative going step from the set HT level down to zero for quarter wave switching
External Trigger In+3.0 to 10.0V min. 10ns f.w.h.m. into 50W
Synchronization OutputTTL approx. 30ns after trigger
Overload Protection(1) Repetition rates above 100kHz
(2) HT Current above 25mA
(3) Output stage fault overload

Protection occurs by automatic removal of the HT supply which can be re-instated by the reset switch
Power InputUniversal 90 - 265V a.c. 47 - 440Hz via fused IEC inlet
Dimensions150(h) x 250(w) x 330(d) (mm) Mass: 6kg
Step Voltage at End of an Open Circuit 50W Line
50W co-axial cable lengthRise-TimeFlat TopFall TimeMaximum Frequency at 2kVMaximum Voltage at 100kHz
125mm5ns175ns400ns80kHz1,700V
250mm5ns160ns500ns66kHz1,500V
500mm<7ns150ns700ns50kHz1,300V
1,000mm<8ns120ns1,000ns40kHz800V

Cutting and Optical Polishing Services

Example of 25mm diameter substrates being polishedLeysop employs a number of highly skilled optical polishing technicians, each with many years of experience of cutting and polishing of a varied range of materials. Using mainly hand polishing techniques for the ultimate control of surface finish and figure, optical surfaces may be routinely produced to better than lambda/10 (633nm) and laser finish scratch-dig of better than 10-5. A wide variety of substrates may be polished and our technicians have experience of materials from the softest (ADP, KD*P) to some of the hardest optical materials (ruby, sapphire, germanium). In fact, the water soluble crystals present special challenges for the optical polisher (for obvious reasons)! Our staff however can produce the highest quality laser grade surfaces as demanded by use in high power laser systems.




Example of laser rod refurbishingWe are very happy to offer contract cutting and polishing services to meet your individual needs. Our equipment includes diamond saws, edging grinders for reducing diameters and producing discs and diamond core drilling. All of these are water free for working the specially critical water soluble crystals used in our Q-switches and modulators. These are all backed by our team of highly skilled technicans who can produce precision optical components to your specification. So please give us a call to discuss your requirements. No job is too big or too small. Although much of our work is optical production based, much of our capacity is also available for those small jobs, perhaps manufacturing a special prism in small quantities, or re-working a laser rod which has suffered optical damage. Please try to send us a drawing of what you need if possible; a picture really does paint a thousand words!


Anti-Reflection Coating and Metalization Services

Coating chamber for thermal evaporation of dielectric ar coatings

In the course of manufacture of the varied range of Leysop products, we are required to apply both anti-reflection coatings for reduction of Fresnel optical losses at air-dielectric interfaces, as well as metal film layers so that electric fields may be applied to the electro-optic devices. We have dedicated coating vacuum plants for each of these processes to eliminate the risk of cross contamination.

Our dielectric coating rig has both optical and crystal monitoring facilities built into the chamber; thicknesses can thus be monitored against the theoretical curves as well as the practical results. This eliminates errors due to the variable stoichiometry which may occur with some thermally evaporated films.

The majority of our anti-reflection coatings are single layers of a thickness equal to a quarter wavelength of light at the operating wavelength. This simple coating offers good adhesion and high laser damage resistance in most cases. Typically, magnesium fluoride is used for glasses and low refractive index substrates such as calcite, whereas yttrium fluoride is used for higher index substrates such as lithium niobate and lithium tantalate. This offers an excellent match to these substrates and a very low loss can be achieved over quite a broad bandwidth. One major advantage of single layer coatings is that even outside the range of optimum performance, the coating performance will never degrade to the point where the substrate is worse than if un-coated. This however may occur with multi-layer coatings.

For applications where loss is critical and the user only wishes to operate at a single wavelength, we can often deposit suitable multi-layer a/r coatings to offer the lowest possible loss. Please be aware however, that these films are usually more highly stressed than the simpler single layer coatings so may not be suitable for some applications. Adhesion may also be compromised, although this is not necessarily the case.

Please feel free to enquire about coatings for your substrates. We do not claim to be coating specialists, our equipment and practices are largely dictated by the requirements of our own devices (particularly the water soluble XDP crystal isomorphs on which we have vast experience of applying coatings). However, for the simpler requirements we can be more flexible than many of the specialists and can offer the turn around and lower chamber costs that make us more cost effective, especially for experimental and short run work.


 

Polarising Optics


Glan-Taylor

GT10 10mm

GT12 12mm

GT15 15mm

GT18 18mm

GT20 20mm

GT25 25mm

GT30 30mm

 

Optical coatings – single layer on input, output and side exit faces, add £50 per face coated. Single polished side exit face, add £90. Double polished side exit face, add £135. Mounted in black anodised cylinder, add £50. Cylinder sizes: 12-25mm , 15, 18, 20-35mm long. 25-50mm , 35mm long. 30-50mm , 45mm long.

 

Brewster Cut Glan-Taylor Low Loss Polarizer

 

GTB10 10mm

GTB12 12mm

 

This polarizer uses a Brewster cut input and output face and an internal interface which is almost at Brewster’s angle for exceptionally low insertion loss. GTB12 12m

 

Orthogonal Output Glan-Taylor in Mount

This polariser has two side exit windows with outputs orthogonal to main beam axis and is mounted in an anodised aluminium alloy housing as standard.

 

GLBS10 9mm clear aperture  

GLBS12 11mm clear aperture

Including single layer anti-reflection coating.

 

Glan-Thompson

Short Version                                             Long Version

GTM8    8 x8x20mm                                  GTML8           8x8x24mm

GTM10   10x 10x25mm                             GTML10        10x10x30mm

GTM12   12 x 12x30mm                            GTML12        12 x 12x36mm

GTM15   15 x15x38mm                             GTML15        15 x 15x45mm

GTM20   20 x20x50mm                             GTML20        20 x20 x 60mm

 

Calcite Wollaston                                    Calcite Rochon

20°Deviation                                               10° Deviation

BSW/C           10mm                                    BSR/C          10mm

BSW/C           12mm                                    BSR/C           12mm

BSW/C          15mm                                     BSR/C           15mm

BSW/C           20mm                                    BSR/C           20mm

 

Quartz Wollaston                                       Quartz Rochon

1°Deviation                                                   0.5°Deviation

BSW/Q          10mm                                     BSR/Q            10mm

BSW/Q          12mm                                     BSR/Q            12mm

BSW/Q          15mm                                     BSR/Q            15mm

BSW/Q          20mm                                     BSR/Q            20mm

 

 

 

Calcite Lyot De-Polariser

CLD10     Two plates 2.5 and 5.0mm thick, axes at 45°    10mm diameter

CLD25     Two plates 2.5 and 5.0mm thick, axes at 45°    25mm diameter

 

 

Quartz Low Order Retardation Plates -Mounted (λ/4-λ/2)

For Stock Items Only

Model          Clear Aperture        Mount Diameter

QWP10            10mm                         25mm

QWP20           20mm                         25mm

QWP25           25mm                          35mm

QWP30           30mm                           40mm

 

High Power Laser Attenuator

HLPA10 9mm clear aperture 

HLPA12 11mm clear aperture

HLPA15 14mm clear aperture

 

30mm Cage system compatible design. Including single layer antireflection coatings.

 

45° Faraday Rotators and Isolators; 5mm Aperture

FOI 5/57             0.5-0.75μm

FOI 5/57             0.75-0.85μm

FOI 5/57             0.85-0.90μm

FOI5/57BB         0.70-0.90μm Broad Band (90°)

FOI 5/57UWB     0.65-1.1μm

FOI 5/711            0.85-1.1μm

 

Electro-Optics

Low Voltage Modulators

EM200A     EM400A

EM200K     EM400K

EM200L      EM400L

 

Transverse Field Lithium Niobate Pockels Cells for Q-Switching

LNQ Crystal 9 x 9 x 25mm, coated for 1064nm

LNQM Crystal 9 x 9 x 25mm, coated for 1064nm

 

Longitudinal Field KD*P Pockels Cells for Q-Switching

EM508           8mm Aperture

EM510         10mm Aperture

EM512         12mm Aperture

EM515         15mm Aperture

EM520          20mm Aperture

 

Compact Longitudinal Field KD*P Pockels Cells for OEM Q-Switching

EM508M        8mm Aperture

EM510M        10mm Aperture

EM512M        12mm Aperture

EM515M        15mm Aperture

EM520M        20mm Aperture

EM510C         10mm Aperture

 

Double Crystal 8mm Pockels Cells for Lower Voltage Q-switching

EM508/2 or EM508M/2 Two crystal 8mm aperture

EM510/2 or EM510M/2 Two crystal 10mm aperture

 

Special Pockels Cells for Pulse Slicing and Pulse Picking

UPC068      6mm aperture ultra fast (180ps) Pockels cell. Fluid

filled or dry, un-coated crystals at 532/1064nm.

UPC068/2   Double crystal version of UPC068 for half voltage

operation. Fluid filled.

EM505         5mm aperture 3 electrode Pockels cell ideal for use

with two avalanche drivers etc. Fluid filled

 

100kHz RTP Q-Switch System (standard AR coating for 1064nm e.g.)

3mm Aperture RTP Q-switch

4mm Aperture RTP Q-switch

6mm Aperture RTP Q-switch

100kHz 2kV Q-switch driver

 

 

Phase Modulators

Phase Modulators PM10-/50MHz - Single frequency

PM50-/100MHz - Single frequency

 

Electro-Optic Deflectors (lithium niobate or lithium tantalate for general applications)

ED1 1mm Aperture 

ED2 2mm Aperture

ED3 3mm Aperture

 

High Laser Damage Electro-Optic Deflector for Q-switching applications

ED1H 1mm Aperture

 

Electronics

Analogue Drivers for Electro-Optic Modulators

M250        M500

M1000      M2500 

M5000

 

High Voltage Generators for Q-Switching

Please enquire about available options – we can offer many solutions for this and other applications.

900V Pulse Generator for Deflector Q-switch

900V, <5ns rise time, up to 20kHz min. prf




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