Optical device and light production method

2:

• The optical device according to claim 1,
• wherein the birefringent element is disposed such that a propagation direction of at least one of the first light and the second light in the birefringent element and an optical axis of the birefringent element intersect each other.

3:

• The optical device according to claim 1,
• wherein the nonlinear optical element of the light generation unit is disposed such that an optical axis of the nonlinear optical element of the light generation unit is parallel to a first virtual plane parallel to the optical axis of the birefringent element and the propagation direction of the at least one of the first light and the second light in the birefringent element or is parallel to a second virtual plane that is orthogonal to the first virtual plane and is parallel to the propagation direction of the at least one light component.

4:

• The optical device according to claim 1,
• wherein the polarization state of one of the first light and the second light incident on the birefringent element is linearly polarized light that is parallel to a virtual plane parallel to the propagation direction of the one light component and the optical axis of the birefringent element.

5:

• The optical device according to claim 1,
• wherein the polarization state of one of the first light and the second light incident on the birefringent element is linearly polarized light that is orthogonal to a virtual plane parallel to the propagation direction of the one light component and the optical axis of the birefringent element.

6:

• The optical device according to claim 1,
• wherein the first light and the second light have different frequencies.

7:

• The optical device according to claim 1,
• wherein the nonlinear optical element of the light generation unit has an incident surface on which the first light and the second light are incident, and
• the control unit controls at least one of the temperature of the birefringent element and the voltage applied to the birefringent element to adjust the phase difference between the first light and the second light in the incident surface of the nonlinear optical element of the light generation unit.

8:

• The optical device according to claim 7,
• wherein the control unit controls at least one of the temperature of the birefringent element and the voltage applied to the birefringent element such that phases of the first light and the second light are matched with each other in the incident surface of the nonlinear optical element of the light generation unit.

9:

• The optical device according to claim 1,
• wherein the third light has a frequency different from the frequencies of the first light and the second light.

10:

• The optical device according to claim 1,
• wherein the nonlinear optical element of the light generation unit generates the third light using a nonlinear optical effect according to the first light and the second light.

11:

• The optical device according to claim 1,
• wherein the frequency of the third light is a sum of the frequency of the first light and the frequency of the second light.

12:

• The optical device according to claim 1,
• wherein the frequency of the third light is a difference between the frequency of the first light and the frequency of the second light.

14:

• The optical device according to claim 1,
• wherein the light emitting unit includes a nonlinear optical element emitting the first light and the second light to be incident on the birefringent element.

15:

• The optical device according to claim 1,
• wherein the light emitting unit includes a nonlinear optical element that generates a second harmonic as the second light on the basis of a fundamental wave and emits the fundamental wave as the first light together with the second light, and
• the nonlinear optical element of the light generation unit generates a second harmonic as the third light on the basis of the incident first light and combines the second light and the third light.

16:

• The optical device according to claim 1,
• wherein the light emitting unit includes a nonlinear optical element that generates fourth light having a polarization state different from the polarization state of the first light or the second light on the basis of the first light and the second light and emits the first light and the second light together with the fourth light, and
• the nonlinear optical element of the light generation unit is disposed such that the first light, the second light, and the fourth light emitted from the birefringent element are incident thereon and combines the third light and the fourth light.

17:

• The optical device according to claim 16,
• wherein the frequency of the third light and the frequency of the fourth light are the sum of the frequency of the first light and the frequency of the second light.

18:

• The optical device according to claim 16,
• wherein the frequency of the third light and the frequency of the fourth light are the difference between the frequency of the first light and the frequency of the second light.

19:

• The optical device according to claim 1,
• wherein the light emitting unit includes a nonlinear optical element that generates, as the second light, light having a polarization state different from the polarization state of the first light or fourth light having the same polarization state as the first light on the basis of the first light and the fourth light and emits the first light, the second light, and the fourth light together, and
• the nonlinear optical element of the light generation unit is disposed such that the first light, the second light, and the fourth light emitted from the birefringent element are incident thereon and combines the second light and the third light.

20:

• The optical device according to claim 19,
• wherein the frequency of the second light and the frequency of the third light are a sum of the frequency of the first light and a frequency of the fourth light.

21:

• The optical device according to claim 19,
• wherein the frequency of the second light and the frequency of the third light are a difference between the frequency of the first light and a frequency of the fourth light.

22:

• The optical device according to claim 1,
• wherein the light emitting unit includes a nonlinear optical element that generates, as fourth light, a second harmonic having a polarization direction different from a second direction on the basis of a fundamental wave including polarized components in a first direction and the second direction orthogonal to each other and emits the polarized component of the fundamental wave in the first direction as the first light and the polarized component of the fundamental wave in the second direction as the second light together with the fourth light, and
• the nonlinear optical element of the light generation unit is disposed such that the first light, the second light, and the fourth light emitted from the birefringent element are incident thereon, generates a second harmonic as the third light on the basis of the incident first light and second light, and combines the third light and the fourth light.

23:

• The optical device according to claim 1,
• wherein the light emitting unit includes a nonlinear optical element that generates the second light having a polarization state different from a polarization state of pump light and fourth light having a polarization state different from the polarization state of the pump light and having a frequency different from the frequency of the second light on the basis of the pump light and emits the pump light as the first light together with the second light and the fourth light, and
• the nonlinear optical element of the light generation unit is disposed such that the first light, the second light, and the fourth light emitted from the birefringent element are incident thereon, generates fifth light having the same polarization state and frequency as the second light and sixth light having the same polarization state and frequency as the fourth light on the basis of the incident first light, second light, and fourth light, combines the second light and the fifth light and combines the fourth light and the sixth light to amplify an intensity of at least one of the second light and the fourth light, and emits the combined light as the third light.

24:

• The optical device according to claim 1,
• wherein the light emitting unit includes a nonlinear optical element that generates fourth light having the same polarization state as pump light and the second light having a polarization state different from the polarization state of the pump light and having a frequency different from a frequency of the fourth light on the basis of the pump light and emits the pump light as the first light together with the second light and the fourth light, and
• the nonlinear optical element of the light generation unit is disposed such that the first light, the second light, and the fourth light emitted from the birefringent element are incident thereon, generates fifth light having the same polarization state and frequency as the second light and sixth light having the same polarization state and frequency as the fourth light on the basis of the incident first light, second light, and fourth light, combines the second light and the fifth light and combines the fourth light and the sixth light to amplify an intensity of at least one of the second light and the fourth light, and emits the combined light as the third light.

25:

• The optical device according to claim 23,
• wherein the control unit controls at least one of the temperature of the birefringent element and the voltage applied to the birefringent element such that the phases of the first light and the second light are matched with each other and the phase of the first light and the phase of the fourth light deviate from each other.

26:

• The optical device according to claim 14,
• wherein the nonlinear optical element of the light emitting unit and the nonlinear optical element of the light generation unit are made of the same material, and
• a direction of an optical axis of the nonlinear optical element of the light emitting unit with respect to incident light is opposite to a direction of the optical axis of the nonlinear optical element of the light generation unit with respect to incident light.

27:

• The optical device according to claim 14,
• wherein the birefringent element includes an incident surface on which the first light and the second light are incident, and
• the optical axis of the birefringent element is inclined with respect to the incident surface of the birefringent element such that walk-off occurring in the nonlinear optical element of the light emitting unit is reduced.

28:

• The optical device according to claim 1,
• wherein the nonlinear optical element of the light generation unit and the birefringent element are joined to each other.

29:

• The optical device according to claim 1, further comprising:
• a light detection unit detecting the light emitted from the nonlinear optical element of the light generation unit,
• wherein the control unit performs feedback control on at least one of the temperature of the birefringent element and the voltage applied to the birefringent element on the basis of a detection result of the light detection unit.

30:

• The optical device according to claim 29,
• wherein the control unit acquires a target value of an intensity of light and performs the feedback control on at least one of the temperature of the birefringent element and the voltage applied to the birefringent element such that the intensity of the light detected by the light detection unit is matched with the acquired target value.