KR20160063977A - pulse width stretcher and chirped pulse amplifier including the same - Google Patents

Abstract

The present invention discloses a pulse width stretcher and a chirped pulse amplifier including the same. The pulse width stretcher may include first and second multiple reflection mirrors and a pulse group-delay dispersion block which is arranged between the first and second multiple reflection mirrors and refracts a pulse laser beam to stretch the pulse width of a pulse laser beam. So, space efficiency can be maximized.

Description

[0001] The present invention relates to a pulse width expander and a chirped pulse amplifier including the same,

The present invention relates to an optical amplifying apparatus, and more particularly, to a pulse width expander for expanding the pulse width of a pulse laser beam and a chirped pulse amplifying apparatus including the same.

In the mid-1980s there was an important optical technological advance overcoming the output power limit of the pulsed laser beam in relation to the damage threshold of the gain medium. It is chirped pulse amplification technology. The chirped pulse amplification technique can provide a pulsed laser beam with significantly higher output power than a conventional pulse amplification technique. A typical chirped pulse amplifying device can generate a pulsed laser beam having a maximum output power of about 1 GW or less. On the other hand, the chirped pulse amplifying device can minimize the influence of the damage threshold of the optical medium by adjusting the pulse width of the pulsed laser beam. Thus, the chirped pulse amplifying device can generate a pulsed laser beam having a maximum output power of about 1 TW or more.

It is an object of the present invention to provide a pulse width expander having multiple passes of a pulsed laser beam.

It is another object of the present invention to provide a pulse width expander capable of maximizing space efficiency and a chirp pulse amplifying device including the same.

The present invention discloses a pulse width expander. The pulse width expander includes a first multiple reflection mirror including a first large-area mirror that reflects the pulsed laser beam, and a first small-area mirror within the first large-area mirror; A second multiple reflection mirror including a second large-area mirror disposed opposite to the first large-area mirror, and a second small-area mirror within the second large-area mirror; And a pulse group delay dispersion block disposed between the first multiple reflection mirror and the second multiple reflection mirror and refracting the pulse laser beam to expand a pulse width of the pulse laser beam.

According to an aspect of the present invention, there is provided a chirped pulse amplifying apparatus comprising: an oscillator for generating a pulsed laser beam; A pulse width compressor disposed apart from the oscillator and compressing the pulse width of the pulse laser beam; A pulse amplifier disposed between the pulse width expander and the oscillator, the pulse amplifier amplifying the intensity of the pulsed laser beam; And a pulse width expander disposed between the pulse amplifier and the oscillator and extending the pulse width of the pulsed laser beam. Here, the pulse width expander includes:

A first multiple reflection mirror including a first large area mirror for reflecting the pulsed laser beam and a first small area mirror in the first large area mirror; A second multiple reflection mirror including a second large-area mirror disposed opposite to the first large-area mirror, and a second small-area mirror within the second large-area mirror; And a pulse group delay dispersion block disposed between the first multiple reflection mirror and the second multiple reflection mirror and for expanding the pulse width of the pulse laser beam by refracting the pulse laser beam.

As described above, the pulse width expander according to the embodiment of the present invention includes a group delay dispersion block for expanding the pulse width of the pulse laser beam by refracting the pulse laser beam reflected between the first and second multiple reflection mirrors . The group delay dispersion block may have multiple passes of the pulsed laser beam between the first and second multiple reflection mirrors. The first and second multiple reflection mirrors and the group delay dispersion block can maximize the space efficiency of the pulse width expander.

FIG. 1 is a diagram illustrating a chirped pulse amplifying apparatus according to the concept of the present invention.
2 is a view showing an example of the pulse oscillator of FIG.
3 and 4 are respectively a perspective view and a side view showing an example of the pulse width expander of FIG.
5 is a perspective view and a side view showing an example of the pulse width expander of FIG. 1;
FIG. 6 is a diagram illustrating an example of the pulse amplifier of FIG. 1;
Figures 7 and 8 are respectively a perspective view and a side view showing the pulse width compressor of Figure 1;

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein but may be embodied in different forms. Rather, the embodiments disclosed herein are provided so that the disclosure can be thorough and complete, and will fully convey the concept of the invention to those skilled in the art, and the present invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

The terminology used herein is for the purpose of illustrating embodiments and is not intended to be limiting of the present invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. It is to be understood that the phrase "comprises" and / or "comprising" used in the specification exclude the presence or addition of one or more other elements, steps, operations and / or elements, I never do that. Further, in the specification, chambers, thin films, and coatings may be understood as general semiconductor and device terms. The reference numerals shown in the order of description are not necessarily limited to those in the order of the preferred embodiments.

Fig. 1 shows a chirped pulse amplifying device 10 according to the concept of the present invention.

Referring to FIG. 1, the chirp pulse amplifying apparatus 10 may include a pulse oscillator 20, a pulse width expander 30, a pulse amplifier 40, and a pulse width compressor 50. The pulse oscillator 20 may generate the pulsed laser beam 100. [ For example, the pulsed laser beam 100 may have about 10 ⁶ pulses 102 per second. The pulse width expander 30 may extend the pulse width 104 of the pulsed laser beam 100. [ The pulse width W may be defined as a time interval at which the intensity and / or the amplitude becomes 1/2 at the rising time and the falling time of the pulse 102. The intensity of the pulse 102 may be varied in the pulse width expander 30, the pulse amplifier 40, and the pulse width compressor 50. The pulse width expander 30 may extend the pulse width 104 per wavelength band of the pulsed laser beam 100. [ The intensity of the pulse 102 can be reduced. For example, the pulse width expander 30 may reduce the intensity of the pulsed laser beam 100 below the damage threshold of the second gain medium (46 of FIG. 6) of the pulse amplifier 40. The pulse amplifier 40 can amplify the intensity of the pulsed laser beam 100. The pulse width compressor 50 may compress the pulse width 104 of the pulsed laser beam 100. For example, the intensity of the pulsed laser beam 100 in the pulse width compressor 50 may be increased by about 10 < ⁵ > to 10 < ⁶ > times greater than the intensity of the pulsed laser beam 100 in the pulse oscillator 20 .

FIG. 2 shows an example of the pulse oscillator 20 of FIG.

Referring to FIG. 2, the pulse oscillator 20 may include a first pump laser 21, a first resonator 24, a first chirp mirror 28, and a first output mirror 29. The first pump laser 21 can generate the first pump light 21a. The first pump light 21a may be provided to the first resonator 24 by the pump light condensing lens 22. [ The first resonator 24 and the first chirp mirror 28 can generate the pulsed laser beam 100 from the pump light 21a. For example, the first resonator 24 may include first and second concave mirrors 23 and 25, and a first gain medium 26. The first and second concave mirrors 23 and 25 can reflect the pulsed laser beam 100. [ Alternatively, the first and second concave mirrors 23 and 25 can amplify the intensity of the pulsed laser beam 100. [ The first gain medium 26 may be disposed between the first and second concave mirrors 23, 25. The first gain medium 26 may oscillate the pulsed laser beam 100. The first chirp mirror 28 may be disposed outside the extension of the first and second concave mirrors 23 and 25 and the first gain medium 26. For example, the pulsed laser beam 100 may be transmitted between the second concave mirror 25 and the first chirp mirror 28. The first chirp mirror 28 may generate the pulses 102 of the pulsed laser beam 100. The first concave mirror 23 may provide the pulsed laser beam 100 to the first output mirror 29. The first output mirror 29 may output the pulse laser beam 100 to the pulse width expander 30. [

FIG. 3 and FIG. 4 show an example of the pulse width expander 30 of FIG.

3 and 4, the pulse width expander 30 may include a first multiple reflective mirror 32, a second multiple reflective mirror 34, and a group delay dispersion block 38. The first and second multiple reflection mirrors 32 and 34 may reflect the pulsed laser beam 100 several times. The group delay dispersion block 38 may be disposed between the first and second multiple reflection mirrors 32 and 34. The group delay dispersion block 38 may increase the pulse width 104 of the pulsed laser beam 100. [

The first and second multiple reflection mirrors 32 and 34 may be spaced apart. The first and second multiple reflection mirrors 32 and 34 may reflect the pulsed laser beam 100 multiple times. For example, the first and second multiple reflection mirrors 32 and 34 may reflect the pulsed laser beam 100 about 24 times. "1" - "24" in FIG. 3 may correspond to reflection points of the pulsed laser beam 100. The distance between the first and second multiple reflection mirrors 32, 34 is about 33.5 cm The pulsed laser beam 100 may travel a distance of about 8 (24 * 33.5 cm) m. The pulsed laser beam 100 may be transmitted through a group delay dispersion block 38. The group delay dispersion The block 38 may have multiple passes 106 of the pulsed laser beam 100. The multiple passes 106 may be spatially parallel rather than being crossed within the group delay dispersion block 38. Multiple passes 106 can extend the transmission and / or refraction length of the pulsed laser beam 100 within the group delay dispersion block 38 without extending the length of the group delay dispersion block 38. Thus, And the second multiple reflection mirrors 32 and 34 and the group delay dispersion block 38 can maximize the space efficiency of the pulse width expander 30. [

The first multiple reflection mirror 32 may include a first large area mirror 31 and a first small area mirror 33. According to one example, the first large area mirror 31 may include a concave mirror. The first large area mirror 31 may have a radius of curvature of about 5 m. The first large area mirror 31 may have a first side hole 31a. The first small area mirror (33) may be disposed in the first large area mirror (31). The first small area mirror 33 may be disposed in the first side hole 31a. For example, the first small area mirror 33 may comprise a flat mirror. The pulsed laser beam 100 may pass through the first multiple reflection mirror 32 through the first side hole 31a.

The second multiple reflection mirror 34 may include a second large area mirror 35 and a second small area mirror 36. According to one example, the second large area mirror 35 may comprise a planar mirror. And the second large area mirror 35 may have the second side hole 35a. The second small area mirror (36) may have a smaller area than the second large area mirror (35). The second small area mirror 36 may be disposed in the second side hole 35a. For example, the second small area mirror 36 may comprise a flat mirror. The pulsed laser beam 100 may pass through the second multiple reflection mirror 34 through the second side hole 35a.

The group delay dispersion block 38 may be disposed between the first and second multiple reflection mirrors 32 and 34. According to one example, the group delay dispersion block 38 may comprise a dielectric cylinder. The group delay dispersion block 38 may comprise silicon oxide. The group delay dispersion block 38 may have a positive group delay variance value for the pulsed laser beam 100. For example, when the pulsed laser beam 100 passes through the group delay dispersion block 38, the transmission time of each pulse of the pulsed laser beam 100 may vary. Because the group delay dispersion block 38 has a different refractive index for each wavelength band of the pulsed laser beam 100. [ The group delay dispersion block 38 may have a group velocity dispersion of the wavelength of the pulsed laser beam 100. The long wavelength of the pulsed laser beam 100 may extend to the front of the pulse 102 with respect to the time axis and the short wavelength of the pulsed laser beam 100 may extend beyond the pulse 102. [ Thus, the pulse width 104 can be extended over the entire wavelength band of the pulsed laser beam 100. [

라고 할 때, 각 주파수 성분의 펄스 레이저 빔(100)의 통과 소요 시간

은 다음과 같이 수학식 1로 표현될 수 있다.The group velocity variance may correspond to the phase change of the pulsed laser beam 100 in the group delay dispersion block 38. [ The phase change of the pulsed laser beam 100 is a function of the frequency component of the pulsed laser beam 100

, The time required for passage of each pulse component of the pulse laser beam 100

Can be expressed by Equation (1) as follows.

는 펄스 레이저 빔(100)의 중심 주파수에 대하여 테일러(Taylor expansion)전개를 하면 다음과 같이 수학식 2로 표현될 수 있다.

Can be expressed by Equation (2) as Taylor expansion developed with respect to the center frequency of the pulse laser beam 100 as follows.

) 펄스 레이저 빔(100)의 초기 위상으로서, 상기 펄스 레이저 빔(100)의 중심주파수의 절대위상일 수 있다. 두 번째 항(

)는 펄스 레이저 빔(100)의 군속도, 즉 중심 주파수의 펄스 레이저 빔(100)이 군지연 분산 블록(38)을 통과하는 소요 시간일 수 있다. 세 번째 항(

)은 펄스 레이저 빔(100)의 주파수에 따른

의 선형변화를 나타내는 항으로 군지연 분산(group delay dispersion, GDD) 값일 수 있다. 군지연 분산 값은 펄스 레이저 빔(100)의 주파수에 따른

의 선형변화에 비례할 수 있다. 예를 들어, 군지연 분산 값이 클수록

의 선형변화가 클 수 있다. 군지연 분산 블록(38)은 펄스 레이저 빔(100)의 군산지연분산 값을 결정할 수 있다. 펄스 레이저 빔(100)의 전체 군지연 분산은 군지연 분산 블록(38)의 군지연 분산 값과, 군지연 분산 블록(38) 내에서의 펄스 레이저 빔(100)의 진행 거리의 곱에 대응될 수 있다. 도시되지는 않았지만, 함수

는 3차 분산(third order dispersion), 내지 N차 분산을 포함할 수 있다. 군지연 분산 값이 계산되면, 3차 분산 내지 N차 분산은 펄스 레이저 빔(100)의 군속도 변화에 거의 영향을 주지 않을 수 있다.The first term (

) Pulse laser beam 100, which may be the absolute phase of the center frequency of the pulsed laser beam 100. The second term (

May be the group velocity of the pulsed laser beam 100, i.e. the time required for the pulsed laser beam 100 at the center frequency to pass through the group delay dispersion block 38. The third term (

) Depends on the frequency of the pulsed laser beam 100

May be a group delay dispersion (GDD) value as a term representing a linear change of the group delay dispersion. The group delay variance value depends on the frequency of the pulsed laser beam 100

Can be proportional to the linear variation of. For example, the larger the group delay variance,

Can be large. The group delay dispersion block 38 may determine the kernary delay variance value of the pulsed laser beam 100. The total group delay dispersion of the pulsed laser beam 100 corresponds to the product of the group delay dispersion value of the group delay dispersion block 38 and the progress distance of the pulsed laser beam 100 in the group delay dispersion block 38 . Although not shown,

Third order dispersion, to N-order dispersion. When the group delay dispersion value is calculated, the third order dispersion or the Nth order dispersion may have little influence on the change in the group velocity of the pulsed laser beam 100. [

)은 수학식 3으로부터 계산될 수 있고, 군지연 분산 값(GDD)과 입력 펄스폭(

)의 변수로 나타내어 진다. On the other hand, the pulse 102 of the pulsed laser beam 100 may have a bell-shaped Gaussian distribution. The group delay dispersion block 38 multiplies the pulse width of the pulsed laser beam 100

) Can be calculated from Equation (3), and the group delay dispersion value (GDD) and the input pulse width

). ≪ / RTI >

)은 불확정성의 원리에 따라

에 대응될 수 있다.

는 펄스 레이저 빔(100)의 중심 파장일 수 있다. c는 빛의 속도(3×10⁸ m/s)일 수 있다.

는 펄스 레이저 빔(100)의 파장의 반치 폭(Full Width Half Maximum)일 수 있다. 확장되는 펄스 폭(

)은 펄스 레이저 빔(100)의 중심 파장(

)과, 반치 폭(

)에 의해 계산될 수 있다. 예를 들어, 중심파장(

)이 800 nm이고, 반치 폭(

)이 100 nm인 펄스 레이저 빔(100)가 군지연 분산 블록(38)을 8m를 통과하면, 펄스 레이저 빔(100)의 펄스 폭(104)은 약 388 ps(피코초)로 확장될 수 있다. 따라서, 펄스 폭 확장기(30)는 군지연 분산 블록(38)의 다중 패스(106)를 이용하여 펄스 폭(104)을 효과적으로 확장시킬 수 있다. Input pulse width (

) Depends on the principle of uncertainty

Lt; / RTI >

May be the center wavelength of the pulsed laser beam 100. c may be the speed of light (3 x 10 ⁸ m / s).

(Full Width Half Maximum) of the wavelength of the pulsed laser beam 100. Expanded pulse width (

Is the center wavelength of the pulsed laser beam 100 (

) And the half-value width (

). ≪ / RTI > For example, the center wavelength (

) Is 800 nm and the half-value width (

The pulse width 104 of the pulsed laser beam 100 can be extended to about 388 ps (picoseconds) if the pulsed laser beam 100 with a pulse width of 100 nm passes through the group delay dispersion block 38 at 8 m . Thus, the pulse width expander 30 can effectively extend the pulse width 104 using multiple passes 106 of the group delay dispersion block 38. [

FIG. 5 shows an example of the pulse width expander 30 of FIG.

Referring to FIG. 5, the first multiple reflection mirror 32 may include a plurality of first small area mirrors 33. The second multiple reflection mirror 34 may include a plurality of second small area mirrors 35. The first and second large-area mirrors 31 and 35, and the group delay dispersion block 38 may be the same as those in FIG.

)이 800 nm이고, 반치 폭(

)이 100 nm인 펄스 레이저 빔(100)이 군지연 분산 블록(38)을 24m를 통과하면, 펄스 레이저 빔(100)의 펄스 폭(104)은 약 1,164 ps로 확장될 수 있다.For example, the first and second multiple reflection mirrors 32 and 34 of the pulse width expander 30 may reflect the pulsed laser beam 100 about 70 times. &Quot; 1 " to " 70 " may correspond to the reflection points of the pulsed laser beam 100. The pulsed laser beam 100 can pass through the group delay dispersion block 38 72 times. The pulsed laser beam 100 can transmit about 24 (72 * 33.5 cm) m in the group delay dispersion block 38. Center wavelength (

) Is 800 nm and the half-value width (

The pulse width 104 of the pulsed laser beam 100 can be extended to about 1,164 ps when the pulsed laser beam 100 having a pulse width of 100 nm passes through the group delay dispersion block 38 at 24 m.

FIG. 6 shows an example of the pulse amplifier 40 of FIG.

Referring to FIG. 6, the pulse amplifier 40 may include second pump lasers 41, first mirrors 42, and a second resonator 44. The second pump lasers 41 may be disposed on both sides of the first mirrors 42 and the second resonator 44. And the second pump lasers 41 can generate the second pump light 41a. The first mirrors 42 may provide the second pump light 41a to the second resonator 44. The frequency of the pulse pumping light 41b may be the frequency at which it is well absorbed in the second media 46. The second resonator 44 can amplify the intensity of the pulsed laser beam 100. According to one example, the second resonator 44 may include first mirrors 43, second mirrors 45, and a second gain medium 46. The first mirrors 43 and the second mirrors 45 may be disposed facing each other. The second gain medium 46 may be disposed between the first and second mirrors 43 and 45. The second gain medium 46 may comprise the same material as the first gain medium 26. The intensity of the pulsed laser beam 100 may gradually increase every time the pulsed laser beam 100 passes through the second gain medium 46. [ On the other hand, the pulse width 104 of the pulse laser beam 100 in the pulse width expander 30 and the pulse amplifier 40 may be the same.

Figures 7 and 8 show the pulse width compressor 50 of Figure 1.

3, 4, 7, and 8, the pulse width compressor 50 may include third and fourth multiple reflection mirrors 52, 54. The third and fourth multiple reflection mirrors 52 and 54 may be disposed facing each other. According to one example, the third and fourth multiple reflection mirrors 52, 54 may include group delay dispersion mirrors that reflect the pulsed laser beam 100. [ The third and fourth multiple reflection mirrors 52 and 54 are arranged such that the third and fourth multiple reflection mirrors 52 and 54 are arranged such that the group delay dispersion value of the group delay dispersion block 38 Lt; RTI ID = 0.0 > delay < / RTI > dispersion value. For example, the third and fourth multiple reflection mirrors 52, 54 may have negative group delay variance values.

According to one example, each of the third and fourth multiple reflective mirrors 52, 54 may comprise low refractive dielectric layers 62 and high refractive dielectric layers 64. The low refractive dielectric layers 62 may have the same refractive index as the group delay dispersion block 38. Low refractive index dielectric layers 62 may comprise silicon oxide (SiO ₂₎ having a refractive index of about 1.4 degree. High refractive dielectric layers 64 may be disposed between the low refractive dielectric layers 62. The high refractive dielectric layers 64 may have a higher refractive index than the refractive index of the low refractive dielectric layers 62. High-refractive dielectric layers 64 may comprise a titanium oxide having a refractive index of about 1.9 degree (TiO _2). The thicknesses of the low refractive dielectric layers 62 and high refractive dielectric layers 64 may be different. For example, the low refractive dielectric layers 62 may have a thickness on the order of one quarter of the wavelength of the pulsed laser beam 100. The high refractive dielectric layers 64 may have a thickness on the order of 1/2 of the wavelength of the pulsed laser beam 100. When the pulsed laser beam 100 has a wavelength of about 800 nm, the low refractive dielectric layers 62 may have a thickness of about 200 nm and the high refractive dielectric layer 64 may have a thickness of about 400 nm.

The third multiple reflection mirror 52 may include a third large-area mirror 51 and third small-area mirrors 53. According to one example, the third large-area mirror 51 may include a concave mirror. The third large-area mirror 51 may have the same radius of curvature as the first large-area mirror 31. The third large-area mirror 51 may have a third hole 51a. The third small area mirrors 53 may be disposed in the third large area mirror 51. And the third small area mirrors 53 can be fixed in the third hole 51a.

The fourth multiple reflection mirror 54 may include a fourth large-area mirror 55 and a fourth small-area mirror 56. According to one example, the fourth large-area mirror 55 may include a flat mirror. The fourth large-area mirror 55 may have a fourth hole. The fourth small area mirrors 56 may be disposed in the fourth large area mirror 55. And the fourth small area mirrors 56 may be fixed in the fourth hole 55a.

The pulsed laser beam 100 may be reflected by the fourth large-area mirror 55 through the third hole 51a. Alternatively, the pulsed laser beam 100 may be reflected by the third small area mirror 53 and then pass through the fourth hole 55a.

)이 약 100nm인 펄스 레이저 빔(100)의 펄스 폭(104)은 약 -42ps로 압축될 수 있다. For example, when the pulsed laser beam 100 has a wavelength of about 800 nm, the third and fourth large-area mirrors 51 and 55 and the third and fourth small-area mirrors 53 and 56 Each time it is reflected, it can have a group delay dispersion value of about -2,000 fs ² . The third and fourth large area mirrors 51 and 55 and the third and fourth small area mirrors 53 and 56 can reflect the pulsed laser beam 100 about 70 times. The third and fourth large-area mirrors 51 and 55 and the third and fourth small-area mirrors 53 and 56 have a total pulse width 104 of the pulse laser beam 100 of -144,000 fs ² Group delay dispersion value. Half width (

The pulse width 104 of the pulsed laser beam 100 of about 100 nm can be compressed to about -42 ps.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the exemplary embodiments or constructions. It can be understood that It is therefore to be understood that the above-described embodiments and applications are illustrative in all aspects and not restrictive.

Claims (14)

A first multiple reflection mirror including a first large-area mirror reflecting the pulsed laser beam, and a first small-area mirror in the first large-area mirror;
A second multiple reflection mirror including a second large-area mirror disposed opposite to the first large-area mirror, and a second small-area mirror within the second large-area mirror; And
And a pulse group delay dispersion block disposed between the first multiple reflection mirror and the second multiple reflection mirror, the pulse group delay dispersion block extending the pulse width of the pulse laser beam by refracting the pulse laser beam. The method according to claim 1,
Wherein the pulse group delay dispersion block comprises a dielectric cylinder. The method according to claim 1,
Wherein the dielectric cylinder comprises silicon oxide. The method according to claim 1,
Wherein the first and second large-area mirrors respectively fix the first and second small-area mirrors, respectively, and have first and second side holes passing the pulsed laser beam, respectively. The method according to claim 1,
The first large-area mirror includes a concave mirror,
Wherein the second large area mirror comprises a flat mirror. An oscillator for generating a pulsed laser beam;
A pulse width compressor disposed apart from the oscillator and compressing the pulse width of the pulse laser beam;
A pulse amplifier disposed between the pulse width expander and the oscillator, the pulse amplifier amplifying the intensity of the pulsed laser beam; And
And a pulse width expander disposed between the pulse amplifier and the oscillator and extending the pulse width of the pulse laser beam,
Wherein the pulse width expander comprises:
A first multiple reflection mirror including a first large area mirror for reflecting the pulsed laser beam and a first small area mirror in the first large area mirror;
A second multiple reflection mirror including a second large-area mirror disposed opposite to the first large-area mirror, and a second small-area mirror within the second large-area mirror; And
And a pulse group delay dispersion block disposed between the first multiple reflection mirror and the second multiple reflection mirror, the pulse group delay dispersion block extending the pulse width of the pulse laser beam by refracting the pulse laser beam. The method according to claim 6,
The pulse width compressor comprising:
A third multiple reflection mirror for reflecting the pulsed laser beam; And
A fourth multiple reflection mirror disposed to face the third multiple reflection mirror and reflecting the pulse laser beam to the third multiple reflection mirror,
And the third and fourth multiplexed reflection mirrors include group delay dispersion mirrors having a group delay dispersion value that is opposite to the group delay dispersion value of the group delay dispersion block. 8. The method of claim 7,
Wherein the group delay dispersion block comprises a dielectric cylinder,
Wherein each of said third and said fourth multiple reflection mirrors comprises:
Low birefringence dielectric layers having the same refractive index as the refractive index of the dielectric cylinder; And
And high refractive dielectric layers disposed between the low refractive dielectric layers and having a refractive index greater than the refractive index of the low refractive dielectric layers. 9. The method of claim 8,
Wherein the low refractive dielectric layer comprises silicon oxide,
Wherein the high refractive dielectric layer comprises titanium oxide. 8. The method of claim 7,
The third multiple reflection mirror comprises:
A third large area mirror; And
And a third small area mirror disposed in the three large area mirrors,
Wherein the fourth multiple reflection mirror comprises:
A fourth large-area mirror facing the third large-area mirror; And
And a fourth small-area mirror disposed in the fourth large-area mirror. 8. The method of claim 7,
And the third and fourth large-area mirrors fix the third and fourth small-area mirrors, respectively, and third and fourth holes passing the pulse laser beam, respectively. The method according to claim 6,
Wherein the first and second multiple reflection mirrors comprise metal mirrors. The method according to claim 6,
Wherein the pulse oscillator comprises:
A first pump laser for generating a first pump light;
A first resonator for generating the pulsed laser beam from the first pump light; And
And a chirp mirror for chirping the pulsed laser beam,
The first resonator comprises:
A plurality of concave mirrors; And
And a first gain medium disposed between the concave mirrors. 14. The method of claim 13,
Wherein the pulse amplifier comprises:
A second pump laser for generating a second pump light; And
And a second resonator for amplifying the intensity of the pump laser beam by resonating the pump laser beam with the second pump light,
Wherein the second resonator comprises:
A plurality of mirrors; And
And a second gain medium disposed between the mirrors and having the same material as the first gain medium.

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