US 12,360,045 B2
Light detecting device and light detecting method
Kazuhiko Misawa, Fuchu (JP); and Terumasa Ito, Fuchu (JP)
Assigned to National University Corporation Tokyo University of Agriculture and Technology, Fuchu (JP)
Appl. No. 17/908,466
Filed by National University Corporation Tokyo University of Agriculture and Technology, Fuchu (JP)
PCT Filed Feb. 26, 2021, PCT No. PCT/JP2021/007554
§ 371(c)(1), (2) Date Aug. 31, 2022,
PCT Pub. No. WO2021/177195, PCT Pub. Date Sep. 10, 2021.
Claims priority of application No. 2020-035276 (JP), filed on Mar. 2, 2020.
Prior Publication US 2023/0100591 A1, Mar. 30, 2023
Int. Cl. G01N 21/65 (2006.01); G02B 27/10 (2006.01); H01S 3/00 (2006.01); H01S 3/30 (2006.01); G01N 21/63 (2006.01)
CPC G01N 21/65 (2013.01) [G02B 27/1006 (2013.01); H01S 3/0085 (2013.01); H01S 3/30 (2013.01); G01N 21/636 (2013.01); G01N 2021/655 (2013.01)] 11 Claims
OG exemplary drawing
 
1. A light detecting device comprising:
a laser light source generating light source pulse beam;
Polarizing Beam Splitter (PBS) and bandpass filter splitting the light source pulse beam into excitation beam, phase-modulated probe beam Lp and reference probe beam Lr;
an excitation pulse light adjusting section executing optical path length modulation that modulates a relative optical path length difference between the excitation beam and at least one of the phase-modulated probe beam Lp and the reference probe beam Lr;
a light modulator phase-modulating the phase-modulated probe beam Lp;
a mirror that reflects the excitation beam back in an optical axis direction, wherein the optical path length modulation is carried out by reciprocally moving the mirror 15 in the optical axis direction at a predetermined amplitude corresponding to 758 nm in a sawtooth wave of a frequency of 300 Hz, and
a detecting section illuminating combined beam, in which the excitation beam, the phase-modulated probe beam Lp and the reference probe beam Lr are combined, onto a sample, and detecting a Raman Signal Asig that is generated,
wherein a delay time between the phase-modulated probe beam Lp and the reference probe beam Lr is a fixed value, and
wherein the excitation pulse light adjusting section executes the optical path length modulation at an optical path length difference that corresponds to an integer multiple of a length corresponding to a unit wavelength of the phase-modulated probe beam Lp or the reference probe beam Lr.