TY - JOUR
AU - Richards, J C S
AB - A small optical lever is described which can detect a change of 10-10 rad in orientation of a 2 mm2 mirror, with a response time of about 0.25 s. A differential cadmium selenide photocell is used with a standard optical grid technique to detect the displacement of the reflected light beam from a 4 V 3.2 W lamp. Transistors are used to stabilize the lamp current and to amplify the signals for a pen recorder. "Noise" arising from convection currents in the light beam and from the photocells appears not to exceed greatly the photon fluctuations in the light beam. Records illustrate the performance of the lever and amplifier in detecting changes in dimension of a crystal of a few times 10-10 cm and changes in refractive index of a gas by a few times 10-9. The system has also been applied to an infra-red detector using the linear expansion of a metallic strip, where the limit for a 5  0.2 mm strip is about 10-11 W for a 1 c/s bandwidth. For this purpose the signal can be differentiated with respect to time, and velocities of down to 30 /annum can be observed. It appears that a displacement of 10-12 cm could be detected.
TI - Recording optical lever
JF - Journal of Scientific Instruments
DO - 10.1088/0950-7671/36/2/312
DA - 1959-02-01
UR - https://www.deepdyve.com/lp/iop-publishing/recording-optical-lever-rz25YBRFIf
SP - 90
VL - 36
IS - 2
DP - DeepDyve
ER -