PHOTOACOUSTO SPECTROSCOPE FOR DETECTING TUNNEL CURRENT

摘要

PURPOSE:To enable measurement in vacuum or measurement of fine change in a material with a small absorption coefficient of light, by determining a deformation of material with respect to irradiation light from a change in a value of a tunnel current flowing between a sample and a detection probe. CONSTITUTION:A part of a monochromatic interrupted light 105 gives intensity A(lambda) and phase phiA(lambda) of a signal with a microprocessor 109 to correct variations in intensity and phase of light. Most of the monochromatic interrupted light 105 is made to irradiate a sample 1, giving a deformation by expansion and contraction of the sample 1 being absorbed thereby. The deformation is detected as change in a tunnel current flowing between a probe 3 positioned by about 1nm away from the sample 1 and the sample 1. A signal thus detected is introduced to a finely adjusting mechanism 4 to give a distance control signal between the sample 1 and the probe 3 while done to the microprocessor 109 to give an intensity B(lambda) and phase phiB(lambda) of the signal. Then, the results of calculation processing to correct a fluctuating component of a light source are outputted to an X-Y recorder 118 and a CRT monitor 117 as intensity and phase.