| 摘要 |
PURPOSE:To improve quantum officiency by providing an amplifier for amplifyng laser light, inputting it in a photodetector after it is amplified and detecting the fine laser light of one photon/pulse through one measurement. CONSTITUTION:The laser light 101 is inducted to a dark box 1 through a visible light shielding filter 2 and only P-polarization component is made to pass by a polarizing device 4 and amplified by an Nd:YAG crystal 5. Then, the light is reflected by a dichroic mirror 7, converted into the linear polarized light of S component by a lambda/4 plate 6 and amplified again by the crystal 5. Since the amplified output consists only of the S component, it is reflected by the polarizing device 4 and detected by an SI type photomultiplier 17 after the light passes through an optical shutter when half wavelength voltage is impressed on a Pockels cell 12. Even fine laser light pulse of one photon/pulse is detected with the photomultiplier 17 through one measurement since it is amplified by the crystal 5. |
