Q-Drive – G&H’s Electro-Optic Pockel Cell Driver
Brent Gross and Phil Marlowe, G&H (Ohio)
Gooch & Housego’s Q-Drive spearheads our development effort to provide a family of Electro-Optical (EO) Pockels cell drivers engineered for performance and durability. Available as an attractively packaged compact, laboratory bench top instrument, as shown in the photograph, the Q-drive makes a valuable addition to a researcher’s optical tools. We also make the device available as an OEM module for incorporation into commercial or custom built laser systems.
When coupled with the appropriate, highly reliable G&H Pockels cell, the Q-Drive serves to intensify the laser output pulse many fold. Q-switched lasers can produce megawatt, or greater, pulses with FWHM durations of only a few nanoseconds, making them highly useful for aesthetic dermatology, LIDAR, scientific research and industrial processes. Aesthetic laser dermatology, consisting of tattoo removal, hair removal and skin resurfacing, comprises the highest growth segment of the laser market with reported sales increases of over 30% per year.
The driver’s base performance specifications include an output voltage range of 1.5 to 4.5kV with a 6 ns rise time and repetition rate of 2.5kHz. Both the enclosed package unit and the board level module have isolated 50ohm trigger inputs for high noise immunity and optimum signal integrity with jitter less than 100ps.
Featuring a differential output that eliminates high DC voltages relative to ground at the Pockels cell, the Q-Drive minimizes insulation stress and stray capacitance effects while, at the same time, increasing safety and reliability.
At only 10 x 12 x 5cm, (4 x 5 x 2in.), not including the provided 24VDC power adapter, the laboratory model takes up very little space. This allows placement near the Pockels cell, reducing detrimental effects of long high voltage wires connected to the electrodes of the cell. The OEM model takes up even less volume, with nominal dimensions of only 8cm (3in.) square and 2.5cm (1in.) high. Furthermore, G&H can customize the board to meet special requirements to permit its incorporation in unique system designs.
The laboratory model prominently displays controls for voltage adjustment and high voltage on/off. LEDs indicate 24 volt power, trigger present and high voltage status. A pair of panel jacks permits monitoring of the high voltage output with a multimeter through a 1V/kV step-down circuit. A remote connector allows remote control of the high voltage with a remote setpoint, on-off control of the high voltage and a duplicate monitor signal.
Controls and signals on the OEM model depend upon the customer’s requirements, but nominally include remote setpoint, high voltage monitor, and high voltage on-off control. LEDs show status. The OEM model’s temperature range extends from -20°C to +55°C, with +70C operation available as an option.
As mentioned earlier, G&H manufactures Q-switches tailored for use with the Q-Drive. Widely recognized as the world leader in the development and supply of electro-optic Pockels cell Q-switches, with over 40 years’ experience and tens of thousands of Pockels cells in the field, G&H maintains full control of the manufacturing process of our KD*P–based Pockels cells, from crystal growth through precision housing manufacture, meticulous assembly and rigorous testing and documentation. In addition to KD*P Pockels cells, which usually operate at repetition rates below several kHz, G&H offers BBO–based Pockels cells for high-average power, high (<600kHz) repetition rate applications, such as laser micro-machining, drilling, and marking. And for the MIR wavelength range we supply CdTe Pockels cells for Q-switching and pulse-picking of infrared light between 3µm and 12µm.