US 12,332,196 B2
Laser light source and photoelectron microscope
Shik Shin, Tokyo (JP); Toshiyuki Taniuchi, Tokyo (JP); Shinichi Imai, Yamanashi (JP); Kazuo Fujiura, Yamanashi (JP); and Yasunori Furukawa, Yamanashi (JP)
Assigned to The University of Tokyo, Tokyo (JP); and Oxide Corporation, Yamanashi (JP)
Appl. No. 17/615,814
Filed by The University of Tokyo, Tokyo (JP); and Oxide Corporation, Yamanashi (JP)
PCT Filed Jun. 1, 2020, PCT No. PCT/JP2020/021660
§ 371(c)(1), (2) Date Dec. 1, 2021,
PCT Pub. No. WO2020/246438, PCT Pub. Date Dec. 10, 2020.
Claims priority of application No. 2019-103808 (JP), filed on Jun. 3, 2019.
Prior Publication US 2022/0276187 A1, Sep. 1, 2022
Int. Cl. G01N 23/227 (2018.01); G02B 21/06 (2006.01); G02F 1/35 (2006.01); H01S 3/00 (2006.01); H01S 3/081 (2006.01)
CPC G01N 23/227 (2013.01) [G02B 21/06 (2013.01); G02F 1/353 (2013.01); H01S 3/0092 (2013.01); H01S 3/0816 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A photoemission electron microscope comprising:
a laser light source configured to emit a coherent light to irradiate a measurement sample;
an irradiation lens system configured to focus the coherent light from the laser light source onto a surface of the measurement sample;
a controller configured to control level of the coherent light; and
a driving mechanism configured to move a position of an irradiation spot of the coherent light on the surface of the measurement sample, wherein
the laser light source comprises:
a first laser light source configured to emit a continuous wave coherent light;
an optical resonator including an optical path in which the continuous wave coherent light is configured to circulate and including a non-linear optical element disposed on the optical path; and
a quasi-continuous wave light source configured to emit a quasi-continuous wave coherent light having a wavelength shorter than that of the continuous wave coherent light and having a near rectangular output waveform, wherein
when the quasi-continuous wave coherent light is incident on the non-linear optical element from outside the optical resonator while the continuous wave coherent light is entering the optical resonator to circulate in the optical path, the coherent light having a wavelength shorter than that of the quasi-continuous wave coherent light is configured to be emitted from the non-linear optical element, and
the controller is configured to cause the coherent light to be in a high level during shooting with the photoemission electron microscope and to be in a low level at least when the driving mechanism moves the position of the irradiation spot of the coherent light on the surface of the measurement sample.