Flexoelectric liquid crystal composition, liquid crystal element, laser inspection system, and method for analyzing test subject

1 . A laser inspection system, comprising:

a first laser emission unit that generates ultrasonic vibration on a surface of a test subject by irradiating the test subject with a pulse oscillation laser;

a second laser emission unit that emits a continuous oscillation laser;

a first beam splitter that is irradiated with the pulse oscillation laser emitted from the first laser emission unit and the continuous oscillation laser emitted from the second laser emission unit and splits the continuous oscillation laser emitted from the second laser emission unit into irradiation light to be irradiated to the surface of the test subject and reference light;

a liquid crystal element that receives reflected light that is the irradiation light irradiated to the surface of the test subject and reflected from the test subject and the reference light, and causes the reflected light and the reference light to interfere with each other;

a detection unit that detects at least one of the irradiation light or the reference light emitted from the liquid crystal element; and

a second beam splitter that is positioned between the test subject and the liquid crystal element, reflects the irradiation light to be split by the first beam splitter toward the test subject, and transmits the reflected light to be reflected by the test subject toward the liquid crystal element; wherein the liquid crystal element includes a liquid crystal film formed by a flexoelectric liquid crystal composition; and a pair of transparent substrates sandwiching the liquid crystal film, and

wherein the flexoelectric liquid crystal composition exhibits photoconductivity, and contains at least one kind of smectic liquid crystal compound; a chiral dopant; and a charge scavenger,

wherein a content of the chiral dopant is 0.1 parts by mass to 5 parts by mass with respect to 100 parts by mass of a total amount of the smectic liquid crystal compound.

2 . A method of analyzing a test subject for analyzing a property of the test subject using the laser inspection system according to claim 1 , the method comprising analyzing a property of the test subject on a basis of a change in intensity of light detected by the detection unit due to interference between the reflected light that is the irradiation light irradiated to a surface of the test subject where ultrasonic vibration is generated and reflected from the test subject and the reference light in the liquid crystal element.

3 . The laser inspection system according to claim 1 , wherein the chiral dopant contains a photoconductive chiral dopant.

4 . The laser inspection system according to claim 3 , wherein the photoconductive chiral dopant contains at least one of a compound represented by a general formula (1) below or a compound represented by a general formula (2) below:

wherein in the general formula (1) and the general formula (2) each of R 1 and R 2 is independently a hydrocarbon group having an asymmetric carbon.

5 . The laser inspection system according to claim 4 , wherein in the general formula (1) and the general formula (2), R 1 and R 2 are a 2-methylbutyl group.

6 . The laser inspection system according to claim 5 , wherein the liquid crystal film has a thickness of 5 μm to 15 μm.

7 . The laser inspection system according to claim 4 , wherein the liquid crystal film has a thickness of 5 μm to 15 μm.

8 . The laser inspection system according to claim 3 , wherein the liquid crystal film has a thickness of 5 μm to 15 μm.

9 . The laser inspection system according to claim 1 , wherein the smectic liquid crystal compound contains a liquid crystal compound exhibiting a smectic C phase.

10 . The laser inspection system according to claim 9 , wherein the liquid crystal film has a thickness of 5 μm to 15 μm.

11 . A laser inspection system, comprising:

a first laser emission unit that generates ultrasonic vibration on a surface of a test subject by irradiating the test subject with a pulse oscillation laser;

a second laser emission unit that emits a continuous oscillation laser;

a first beam splitter that is irradiated with the pulse oscillation laser emitted from the first laser emission unit and the continuous oscillation laser emitted from the second laser emission unit and splits the continuous oscillation laser emitted from the second laser emission unit into irradiation light to be irradiated to the surface of the test subject and reference light;

a liquid crystal element that receives reflected light that is the irradiation light irradiated to the surface of the test subject and reflected from the test subject and the reference light, and causes the reflected light and the reference light to interfere with each other; and

a detection unit that detects at least one of the irradiation light or the reference light emitted from the liquid crystal element; and

a second beam splitter that is positioned between the test subject and the liquid crystal element, reflects the irradiation light to be split by the first beam splitter toward the test subject, and transmits the reflected light to be reflected by the test subject toward the liquid crystal element;

wherein the liquid crystal element includes a liquid crystal film formed by a ferroelectric liquid crystal composition and a pair of transparent substrates sandwiching the liquid crystal film.

12 . A method of analyzing a test subject for analyzing a property of the test subject using the laser inspection system according to claim 11 , the method comprising analyzing a property of the test subject on a basis of a change in intensity of light detected by the detection unit due to interference between the reflected light that is the irradiation light irradiated to a surface of the test subject where ultrasonic vibration is generated and reflected from the test subject and the reference light in the liquid crystal element.