HCP utilizes periodically poling lithium niobite (ppln) technique to provide an easy to use of EO modulator to customer. With applying the electric field in y-axis of ppln crystal, the angle between ppln optical axis and the input laser polarizationit has small rotation. This small rotated angle grows when the laser beam propagates in ppln, then cause output beam polarization has large amount of polarization rotation. Different from pocket cell device which needs to apply voltage above kV level, a well-designed EO ppln modulator can provide Vpi in only ~100 Volts level, and the response time is up to 10 kHz. Due to the electrical control property, it can use as an optical shutter with no vibrational noise. Even better than mechanical shutter, EO ppln modulator can modulate laser polarization in a continuous way with fast response time, which mean that it can be used as a power stabilizer or it can give a small modulation in laser beam to provide lock-in amplifier for used. The other application of it is put it into an optical cavity as an active Q-switching device. In previously study, due to the high speed response and high damage threshold of ppln, this kind of Q-switching laser can generate more than 200 uJ pulse energy within few nano-seconds.
Fig. 1 Input voltage v.s output power with cross polarizers. The extinction ratio is more than 20dB.
Features :
Ø Available wavelength visible to near-IR
Ø Extinction ratio : > 200 : 1
Ø Fiber coupled input/output
Ø Low Vp : < 150V in bulk (10V in WG) configuration
Application :
Ø Ultra narrow bandpass filter : < 1 nm (FWHM)
Ø Optical shutter with no vibrational noise
Ø Signal modulation for lock-in amplifier purpose
Ø Power stabilizer/noise eater
Active Q-switching device