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HIGH VOLTAGE PULSE GENERATOR – MODEL 8025RS

admin — Wed, 21 Oct 2009 12:11:37 +0000

HIGH VOLTAGE PULSE GENERATOR

The 8025RS Variable Width High Voltage Pulse Generator utilizes highly reliable MOSFET, solid state
elements to provide adjustable width, high voltage pulses with fast, symmetrical rise and fall times.
The instrument is useful with electro-optic light modulators such as Lasermetrics’ Series 1040,
1050, 1145, 1147 and 1150 Pockels cells in many applications: laser pulse gating, slicing, and shaping;
and Q-Switching with post-lasing suppression. The 8025RS is also compatible with other low
capacitance, two terminal devices such as piezoelectric transducers.
The 8025RS employs a low jitter, differential high voltage MOSFET switching amplifier which is
triggered from an external event or synchronizing signal. Two trigger inputs are available: a high level
300 S, 5 to 24 volt input; and a 50 S, 5 volt, TTL compatible input. Trigger polarity is +/- selectable.
The 8025RS provides output voltages which are adjustable by means of a front panel control and
meter. Output pulse voltage is insensitive to trigger voltage amplitude. An output pulse will be generated
when the trigger voltage exceeds the minimum level specified to activate the input circuits.
Over the full range of delays and pulse widths, rise and fall times are maintained at less than 15
nanoseconds for output pulse amplitudes between 1.0 and 5.0 kV and pulse repetition rates up to 500
pps.

Two modes of operation are available:
DIRECT mode: internal delay and pulse width functions are disabled and the output pulse width
follows the width of the input trigger pulse. Pulse width range in the DIRECT mode is from about 50
nsec to infinity. Pulse width can be changed from pulse to pulse.
SELECT mode: an output pulse is activated by the leading edge of the trigger pulse. When set to the
SELECT mode, a front panel adjustable in-out delay enables the user to delay the occurrence of the
output pulse and select where, in the optical pulse, slicing, gating, or Q-switching occurs. Output pulse
widths are continuously adjustable from less than 0.1 µs to 999.9 µs.

HIGH VOLTAGE PULSE GENERATOR MODEL 8025 RS DATA SHEET (PDF)

High Repetition Rate Laser Pulse Gating Systems – 5100ERW SERIES

admin — Wed, 21 Oct 2009 11:55:02 +0000

10 kHz, 20 kHz, 50 kHz, 100 kHz
LASER PULSE GATING SYSTEMS

Repetition Rates up to 100 kHz

≤ 4 nanosecond Rise & Fall Times

Adjustable Output Voltage

Pulse Width Range 6 ns to >1 :s

EMI/RFI Suppressed

Wavelength Range: 200 nm to 1650 nm

Designed for regenerative laser amplifier seeding and pulse extraction, 5100ERW Systems are valuable for
laser pulse picking/chopping, mode locked pulse gating, Q-switching and cavity dumping. The systems
are effective in both intracavity and extracavity applications and exhibit rise and fall times as fast as
3 ns. They offer the latest technology in reliable, solid state, high voltage switching design and superior
electro-optic Pockels cells.
Series 5100ERW Systems, available in 4 repetition rate/voltage ranges, utilize high speed, HV MOSFET
switching circuits and Pockels cell technology developed and refined at FastPulse Technology
through decades of manufacturing and improving its Laser Pulse Gating Systems. These systems are
noted for convenience, longevity, reliability, and noisefree operation.
5100ERW System High Voltage MOSFET Switching Modules are configured for operation at voltages
suitable for half wave operation of RTP (Rubidium Titanyl Phosphate) E-O modulators over their useful
spectral range of about 550 nm to 2000 nm. The systems will also accommodate BBO (β Barium Borate)
modulators operating in the range of 200 nm to approximately 532 nm. By simply adjusting the front
panel HV control, the user can operate the system over the full range of voltages – from less than the
quarter wave voltage to more than the half wave voltage – without loss of efficiency or increased rise or
fall times. Half wave retardation corresponds to 900 rotation of the incoming polarization plane. Operation
in the half wave mode may obviate the usual requirement for a quarter or half wave plate in the
optical train in many regenerative amplifier configurations.

Series 1147 Pockels cells utilize RTP (Rubidium Titanyl Phosphate), noted for its ability to produce optical
switching without superimposing photoelastic ringing on the transmitted beam. RTP modulators use two
crystals, a configuration that provides excellent thermal compensation and stability with low operating
voltages.
Series 1150 BBO Pockels cells utilizing Beta Barium Borate crystals are currently available in aperture sizes of 3 and 4 mm diameters. BBO is noted for its very low piezoelectric response, ability to tolerate high average power and operate in the UV spectrum.
Since BBO requires significantly higher voltages than RTP, aperture sizes are limited to about 4 mm.
The Model 5100ER Power Supply/Timing Generator provides all of the voltages and timing functions
necessary for controlling time delay, pulse width and operating voltage. It accepts trigger signals for a
variety of sources including PIN photodiodes. All controls are located in the PS/TG cabinet which can
be mounted in a rack or used on a bench top.
The 5100EMW Optical Head Assembly contains the Pockels cell mounted on a gimbal for precision pitch
and azimuth positioning and the HV MOSFET Switch Modules. The OHA is virtually noise-free which
makes it very desirable in applications that cannot tolerate radiated or conducted EMI/RFI. The OHA is
provided with two water connections which can be used in conjunction with the laser cooling system.
5100ERW Systems are shipped with a Users Manual and a set of interconnecting cables.

SERIES 5100ERW High Repetition Rate Laser Pulse Gating Systems DATA SHEET (PDF)

BBO Pockels Cell Q-Switches 1150 Series

admin — Tue, 20 Oct 2009 20:05:18 +0000

Wide Spectral Range 250 nm to 1100 nm
High Extinction Ratio
Negligible Piezoelectric Response
High Damage Threshold
High Average Power Capability
Single & Double Crystal Configurations

BBO (Beta Barium Borate) is noted for its excellent
optical quality and low strain birefringence. This
results in high extinction ratios and low wavefront
distortion. Low absorption provides excellent
transmission efficiency in the UV and near IR. Qswitches
fabricated from BBO can be operated at
high repetition rates and high average power.
Operation of BBO modulators and Q-switches from
single shot to repetition rates of more than 50 kHz
is possible with negligible piezoelectric response.
Series 1150 devices are compatible with
FastPulse’s Laser Pulse Gating Systems. They are
used in regenerative laser amplifiers for seeding and
gating, Laser Pulse Chopping and Polarization
Rotation applications. One advantage of BBO
devices is that they do not induce significant
piezoelectric ringing on the transmitted laser beam.
BBO has a useful optical wavelength range from
250 nm to 2100 nm. Transmittance, in the 350 to
1100 nm range, with “V” type narrow band, high
efficiency Anti-Reflection coated windows is
approximately 98.5%.
Typical intrinsic extinction ratios of single crystal
BBO devices are greater than 1000:1 (>30 db)
measured at 633 nm. Single pass wavefront
distortion is <1/8 wave at 633 nm. Thermal
stability is excellent over a broad temperature
range. BBO crystals are slightly hygroscopic and in
many applications must be enclosed in a sealed
housing. In a dry, appropriately clean, dust-free,
enclosure, all devices within the series can be used
without protective windows.

The damage threshold of BBO is of the same order
as deuterated KD*P and RTP, approximately 850
MW/cm2 for a 10 nanoseconds wide Q-switched
pulse at 1064 nm. In gating applications with
laser pulses <100 picoseconds, the damage
threshold is in the 10 GW/cm2 range.
Driving voltages required for BBO crystals to attain
1/4 or ½ wave retardation can be significantly
higher than for KD*P, Lithium Niobate and RTP
crystal devices. Reduced voltage operation is
attained by use of a transverse field configuration
where required drive voltage becomes a function
of crystal dimensions: the ratio of width between
electrodes to overall crystal length.
The 1150 Series has an industry standard 35 mm
diameter, convenient for optical mounts. The
physical size is identical with FastPulse’s Series
Q1059P KD*P and 1147 RTP devices and may
easily replace them in many of the company’s E-O
systems. Series 1150 devices are being used in
the company’s Models 5046, 5057 and 5100
Series Laser Pulse Extraction/ Chopping Systems,
as well as the 5048, 5056, and 5060 Q-switching
Systems and 8025S HV Generator. All of these
drivers provide pulsed high voltages with zero DC
voltage applied to the crystal.

1150 SERIES BBO POCKELS CELL Q-SWITCHES DATA SHEET (PDF)

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