TEMPERATURE CONTROL APPARATUS FOR OPTICAL CRYSTAL
A temperature control apparatus for optical crystal can employ a general temperature control element as is, can be controlled by a single temperature sensor and is applicable to patterns that produce complex temperature distributions. This temperature control apparatus has an optical crystal ( 100 ) that allows a beam to transmit inside the optical crystal, a temperature control element (not shown) that generates or absorbs heat and a heat conducting element ( 101 ) that is arranged between the temperature control element and the optical crystal ( 100 ) and that conducts heat between the temperature control element and the optical crystal ( 100 ), and the heat conducting element ( 101 ) conducts different amounts of heat depending on locations in the heat conducting element to reduce the temperature variation in the optical crystal ( 100 ).
1 . A temperature control apparatus for optical crystal, comprising:
an optical crystal that allows a beam to transmit inside the optical crystal;
a temperature control element that generates or absorbs heat; and
a heat conducting element that is arranged between the temperature control element and the optical crystal and conducts heat between the temperature control element and the optical crystal,
wherein the heat conducting element conducts different amounts of heat depending on locations in the heat conducting element to reduce a temperature variation in the optical crystal.
2 . The temperature control apparatus for optical crystal according to claim 1 , wherein the heat conducting element conducts different amounts of heat between locations in the heat conducting element meeting an input end and an output end of the beam in the optical crystal.
3 . The temperature control apparatus for optical crystal according to claim 1 , wherein, in the heat conducting element, at least one of thermal resistance and thermal capacity varies depending on locations in the heat conducting element.
4 . The temperature control apparatus for optical crystal according to claim 1 , wherein, in the heat conducting element, at least one of a cross section and a substance varies depending on locations in the heat conducting element.
5 . The temperature control apparatus for optical crystal according to claim 1 , wherein a thickness of the heat conducting element varies depending on locations in the heat conducting element in relationship to the optical crystal.
6 . The temperature control apparatus for optical crystal according to claim 1 , wherein a concentration of a substance contained in the heat conducting element varies depending on locations in the heat conducting element in relationship to the optical crystal.
7 . The temperature control apparatus for optical crystal according to claim 1 , wherein the heat conducting element is comprised of a plurality of elements in which at least one of thermal resistance and thermal capacity varies due to a difference between substances.
8 . The temperature control apparatus for optical crystal according to claim 1 , further comprising a temperature sensor that measures a temperature of the optical crystal,
wherein the temperature control element controls an amount of heat generated or an amount of heat absorbed according to a measurement result in the temperature sensor.
9 . The temperature control apparatus for optical crystal according to claim 2 , wherein:
when an amount of heat generated at the input end inside the optical crystal is less than an amount of heat generated at the output end,
the temperature control element generates heat; and
the heat conducting element conducts more heat in a location in the heat conducting element meeting the input end of the beam in the optical crystal than in a location in the heat conducting element meeting the output end of the beam in the optical crystal.
10 . The temperature control apparatus for optical crystal according to claim 2 , wherein:
when an amount of heat generated at the input end inside the optical crystal is smaller than an amount of heat generated at the output end,
the temperature control element absorbs heat; and
the heat conducting element conducts more heat in a location in the heat conducting element meeting the output end of the beam in the optical crystal than in a location in the heat conducting element meeting the input end of the beam in the optical crystal.
11 . The temperature control apparatus for optical crystal according to claim 2 , wherein:
when an amount of heat generated at the input end inside the optical crystal is greater than an amount of heat generated at the output end,
the temperature control element generates heat; and
the heat conducting element conducts more heat in a location in the heat conducting element meeting the output end of the beam in the optical crystal than in a location in the heat conducting element meeting the input end of the beam in the optical crystal.
12 . The temperature control apparatus for optical crystal according to claim 2 , wherein:
when an amount of heat generated at the input end inside the optical crystal is greater than an amount of heat generated at the output end,
the temperature control element absorbs heat; and
the heat conducting element conducts more heat in a location in the heat conducting element meeting the input end of the beam in the optical crystal than in a location in the heat conducting element meeting the output end of the beam in the optical crystal.
13 . The temperature control apparatus for optical crystal according to claim 1 , wherein:
the optical crystal allows a first beam and a second beam with a different incident intensity from the first beam, to transmit in the optical crystal; and
the heat conducting element conducts different amounts of heat between locations in the heat conducting element meeting a first beam end and a second beam end in the optical crystal to reduce a temperature variation inside the optical crystal.
14 . The temperature control apparatus for optical crystal according to claim 1 , further comprising two pairs of the temperature control element and the heat conducting element,
wherein the optical crystal is sandwiched between the two pairs.
15 . The temperature control apparatus for optical crystal according to claim 1 , wherein the optical crystal has a wavelength conversion function.
16 . The temperature control apparatus for optical crystal according to claim 15 , wherein the optical crystal comprises a harmonic generation element.
17 . The temperature control apparatus for optical crystal according to claim 15 , wherein the optical crystal comprises a sum frequency generation element.
18 . The temperature control apparatus for optical crystal according to claim 15 , wherein the optical crystal comprises a difference frequency generation element.
19 . The temperature control apparatus for optical crystal according to claim 15 , wherein the optical crystal comprises an optical parametric amplification element.