• ≤ 3 Nanosecond Output Rise time
• Single Shot to 5 kHz Repetition Rates
• EMI/RFI Shielded Enclosure
• 5 kV & 8 kV Output Voltage Models
• Works on +24 VDC Power Supply
• High Reliability – >10 Year Lifetime

Model 5056 Q-switch Driver Modules integrate high voltage MOSFET circuits and self-contained
miniature high voltage power supplies which require only +24 volts DC input. Trigger signals
can be TTL level voltages. The 5056 is intended for stand-alone operation with the company’s
Series 1058, 1059, 1145, 1147 and 3900 electro-optic Q-switches operating at repetition
rates between single-shot and 5 kHz repetition rates. It will also drive similar Pockels cells from
other manufacturers. All circuits are packaged in an electrically shielded enclosure which
attenuates EMI/RFI to minimize radiated and conducted switching noise. The 5056 Output
voltage is conveniently adjusted by a front panel mounted miniature potentiometer.
The 5056 features a balanced output, i.e., there are 2 independent output connections, one for
each terminal on the Q-switch. The static, unswitched HV outputs have identical HV DC
levels which produce a zero net differential voltage across the crystal. Two other modes of
operation are available without modifications.
Referring to circuit diagram on page 2; when a trigger signal is applied, Side 1 switches from the
pre-adjusted HV level to ground and then, between laser pulses, is allowed to recover to its
original value.
Side 2 always remains at the original HV level so that during the time Side 1 is at the ground level
(‘ON’ Time), pre-set retardation voltage is applied to the crystal. The Q-switched pulse is
generated during the ‘ON’ time. Given an appropriate Q-switch, the 5056 permits
operation at the ¼ or ½ wave retardation voltages or at any voltage in this range. The
8,000 Volt Model 5056-8 will produce pulsed voltages suitable for ½ wave retardation at 1064 nm.

MODEL 5056 SELF-CONTAINED HV SWITCHING MODULE Q-SWITCH DRIVER DATA SHEET (PDF)

SELF-CONTAINED Q-SWITCHING SYSTEMS – MODEL 5055EH Data sheet (pdf)

• Pulse Voltages up to 8 kV
• Repetition Rates up to 5 kHz
• Completely Solid State
• Rise times less than 10 nanoseconds
• Wavelengths from 300 nm to 2500 nm
• Operates safely with KD*P, CdTe, BBO LiNbO3 and other Q-switch materials
• Available with EMI/RFI suppressed HV Driver / Optical Head Assembly.

Meets European CE Mark requirements

5048 System design applies the latest technology in high voltage field effect transistor circuits.
Capable of switching speeds of 5 nanoseconds and operation at up to 5 kHz, 5048 Systems provide
versatility, high reliability, and ease of use.
Systems are available with KD*P Q-switches for operation at wavelengths ranging from 300 nm to
1100 nm or with lithium niobate Q-switches for wavelengths from 700 nm to 2500 nm. Wavelength
range for a particular crystal material is a function of the anti-reflection coatings on the Q-switch.
Brewster angle cut lithium niobate crystals are available for use over the full range of crystal
transmission.
5048 Systems consist of a Power Supply / Pulse Timing Generator, a HV Pulse Output Module and
a Q-switch. A Glan-Laser Air Spaced Polarizer may also be specified. The HV Pulse Module should be
in close proximity to the Q-switch and the Power Supply / Timing Generator is remotely located .
5048 systems can operate over a wide range of output pulse voltages with no change in the output
pulse waveform. A unique characteristic of the FET HV output switches is that the output pulse rise time
remains constant over the full range of output voltages.
Pulsed output voltage of the HV Switching module can be manually adjusted by a front panel control
on the power supply to accommodate quarter wave or half wave operation. This may be accomplished
for wavelengths up to 2500 nm for lithium niobate Q-switches and up to 1100 nm for KD*P Qswitches.
KD*P Q-switches with sol gel antireflection coatings on the crystal are recommended for use with large
beam diameters (>8 mm) and where peak power densities of more than 750 MW/cm2 (#10 nsec
pulse width) are present. Lithium niobate is recommended for applications with high repetition
rates (>100 pps) and peak power densities of <250 MW/cm2.
For OEM and other applications where the HV Switching Module and Q-switch are enclosed in a
shielded enclosure, the configuration pictured above is recommended. Where the Module and Qswitch
are not so enclosed and high voltage switching noise must be suppressed, the Optical
Head Assembly enclosure shown on the following page should be specified. This enclosure complies
with all requirements of the new European EMC regulations for radiated and conducted emissions.

• 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.

• No Piezoelectric Ringing

• High Damage Threshold

• High Extinction Ratio

• Low Insertion Loss

• Non-Hygroscopic

• Thermally Compensated

RTP (rubidium titanyl phosphate – RbTiOPO4), used in the company’s 1147 Series Pockels cells,
is a very desirable crystal material for electrooptic modulators and Q-switches. It combines
several features of KD*P and Lithium Niobate and has one major advantage over both: RTP exhibits
virtually no piezo-electric effect with electrical signals between DC and 100 kHz. There is no
ringing superimposed on the transmitted optical beam passing through the crystal. Modulators
and Q-switches made with RTP can be utilized with high power lasers operating at high repetition rates.
Freedom from piezoelectric ringing enables the use of RTP devices in high repetition rate mode
locked laser pulse extraction, laser pulse slicing, chopping and gating systems as well as in Qswitching
applications. Tests conducted at up to 100 kHz reveal no ringing in the optical waveform.
RTP has a useful optical wavelength range from 350 nm to 4300 nm. Transmittance, in the 400
to 1100 nm range, with hard, “V” type high efficiency Anti-Reflection coatings is 98.5%.
Standard AR wavelengths, at the present time, are 1064 nm and 700-900 nm. A-R coatings for other wavelengths are available.
Typical extinction ratios of RTP devices are greater than 200:1 (>20 db) measured at 633
nm. Wavefront distortion is <1/8 Wave at 633 nm. Thermal stability is excellent over a broad
temperature range. The electro-optic coefficient for RTP is temperature insensitive from about 10
0C to more than 50 0C. Because RTP crystals are not hygroscopic, in an appropriately clean, dustfree,
enclosure, all devices within the series can be used without protective windows.

The damage threshold of RTP is of the same order as deuterated KD*P, 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.
Operating voltages for the 1147 Series are lower than those experienced for KD*P and BBO in the
same aperture sizes. A typical device (Model 1147-6-1064) with a 5.5 mm clear aperture and
AR coatings for 1064 nm has a half wave retardation voltage of 2400 Volts. Capacitance is
also low: for the Series 1147, it is about 5 picofarads. RTP has a high (>1011 Ohms)
resistivity and does not exhibit “gray track” laser damage.
The 1147 Series has an industry standard 35 mm diameter, convenient for optical mounts. The size
is compatible with the company’s Series 1059 KD*P devices and may be easily replace them in
many of the company’s E-O systems.
Series 1147 devices are being used in the FastPulse Technology’s Models 5046E, 5046SC,
and 5057 Laser Pulse Extraction / Chopping Systems, as well as the 5048, 5056, and 5060
Q-switching Systems and 8025S HV Generator.

1147 SERIES RTP ELECTRO-OPTIC MODULATORS AND Q-SWITCHES DATA SHEET (PDF)