Shutters Kerr cell

Frequently it is as necessary to cut off the illumination as quickly and precisely as it is to turn it on. Internal electro-shuttering, such as accomplished with the Faraday and Kerr cells, can be synchronized with the camera and event exactly as needed (Ref 17). However, as mentioned1 above, cameras such as the Beckman/ Whitley framing camera as well as most continuously writing streak cameras, run the risk of incurring double exposures (Ref 13). 

There is another way to obtain giant laser pulses of a few ns duration, known as active Q-switching. The shutter is an electro-optical cell which is triggered at some preset time after the pump flash. These electro-optical shutters are Kerr cells or Pockels cells. 

The Kerr shutter consists of a Kerr cell filled with a liquid, such as nitrobenzene, placed between two crossed polarizers the electric field is arranged to be perpendicular to the axis of the light beam and at 45° to the axis of the polarizers. In the absence of a field there is no optical path through the device. When the field is switched on the nitrobenzene becomes doubly refracting and a path opens between the crossed polarizers. 

Using powerful polarized light pulses instead of electrical pulses to induce birefringence in traditional Kerr cell liquids, an optical Kerr shutter has been developed with wide ranging applications to picosecond measurements [11.22]. 

Kerr Shutter Experiment. The NLO properties of DEANST was also investigated through an optical Kerr shutter experiment. The optical Kerr shutter has the advantages of simple construction and fast response time. DEANST dissolves easily in many solvents. A saturated sample in a DMF (40 wt%) or in a nitrobenzene (30 wt%) was investigated in the Kerr shutter experiment. Powders of DEANST were dissolved in these solvents. The sample solution was poured into a silica glass cell of 1 mm thickness. 

The infrared and green pulses are subsequently separated by a dichroic beam splitter. The infrared pulses travel directly to the ultrafast optical kerr effect shutter (24) while the green pulses are diverted through an optical delay line which consists of one movable and two fixed prisms. The shutter consists of a cell of carbon disulfide placed between two crossed polarizers,... 

---