WO2001005003A1 - Dispositif a laser - Google Patents

Dispositif a laser Download PDF

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Publication number
WO2001005003A1
WO2001005003A1 PCT/JP2000/004632 JP0004632W WO0105003A1 WO 2001005003 A1 WO2001005003 A1 WO 2001005003A1 JP 0004632 W JP0004632 W JP 0004632W WO 0105003 A1 WO0105003 A1 WO 0105003A1
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WO
WIPO (PCT)
Prior art keywords
light
laser device
group velocity
velocity dispersion
laser
Prior art date
Application number
PCT/JP2000/004632
Other languages
English (en)
Japanese (ja)
Inventor
Tetsuya Motegi
Tadashi Okuno
Akira Watanabe
Yuichi Tanaka
Original Assignee
Oyokoden Lab Co., Ltd.
Kikuchi, Kazuro
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Oyokoden Lab Co., Ltd., Kikuchi, Kazuro filed Critical Oyokoden Lab Co., Ltd.
Priority to JP2001509126A priority Critical patent/JP4442791B2/ja
Publication of WO2001005003A1 publication Critical patent/WO2001005003A1/fr

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
    • H01S3/11—Mode locking; Q-switching; Other giant-pulse techniques, e.g. cavity dumping
    • H01S3/1106—Mode locking
    • H01S3/1112—Passive mode locking
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/005—Optical devices external to the laser cavity, specially adapted for lasers, e.g. for homogenisation of the beam or for manipulating laser pulses, e.g. pulse shaping
    • H01S3/0057—Temporal shaping, e.g. pulse compression, frequency chirping
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S2301/00—Functional characteristics
    • H01S2301/08—Generation of pulses with special temporal shape or frequency spectrum
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/02—Constructional details
    • H01S3/04—Arrangements for thermal management
    • H01S3/042—Arrangements for thermal management for solid state lasers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
    • H01S3/08—Construction or shape of optical resonators or components thereof
    • H01S3/081—Construction or shape of optical resonators or components thereof comprising three or more reflectors
    • H01S3/0813—Configuration of resonator
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
    • H01S3/105—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating by controlling the mutual position or the reflecting properties of the reflectors of the cavity, e.g. by controlling the cavity length

Definitions

  • the present invention relates to a novel portable laser device capable of outputting ultrashort pulse light as a light source for a microscope and a light source for two-photon absorption lithography via an optical fiber. More specifically, an ultrashort pulsed laser beam having a narrow pulse width of, for example, 100 femtoseconds is output through an optical fiber without expanding the pulse width.
  • the present invention relates to a laser device mounted on a single housing. Background art
  • the output of a high-power solid-state laser is often directly output as a beam in space.
  • the beam of a mode-locked titanium sapphire laser that outputs a pulse width of 100 femtoseconds, an extremely narrow optical pulse, a so-called femtosecond optical pulse has conventionally been used. It is, however, c has been outputted to the space, recently, applications and to the microscope light source and hitting the like application to a probe microscope, femtosecond optical pulses of the optical fiber (hereinafter, simply will Moi and fibers) in Need to be transmitted.
  • an optical pulse with a short time width in the femtosecond region is composed of many wavelengths propagating while maintaining the same phase.
  • light pulses having a certain wavelength width, distributed from long wavelengths to short wavelengths, and having a time width in the femtosecond region are formed by light of wavelength groups traveling in the same phase.
  • the wavelength width of an optical pulse with a center wavelength of 800 nm and a time width of less than 100 fumtoseconds at full width at half maximum of light intensity is more than 10 nm at full width at half maximum of light intensity per wavelength.
  • the long wavelength component of the optical pulse advances faster than the short wavelength component. Therefore, the length of the fiber was reduced to several meters. Even so, the femtosecond pulses quickly spread to picosecond pulses.
  • the group velocity dispersion controller that has the same negative group velocity dispersion as the positive group velocity dispersion inside the fiber has the optical pulse.
  • the pulse width should be widened. That is, the group velocity dispersion controller creates a state in which the long wavelength component is delayed with respect to the short wavelength component, and then introduces the pulsed light into the optical fiber. In this way, the pulse width can be returned to femtoseconds near the end of the fiber.
  • a conventional laser device that outputs ultrashort pulse light is configured by combining a laser oscillator, a group velocity dispersion control device, and an optical fiber.
  • the laser oscillator and the group velocity dispersion controller described above were mounted in a single portable case due to the difficulty of adjustment work and the difficulty of ensuring stability in the usage environment. It was considered difficult, and each unit was provided in a separate case, such as a laser device and a group velocity dispersion control device.
  • Each unit including such an optical fiber is placed on an optical bench on an anti-vibration table, and by precisely adjusting the optical axis between these units, a required optical system is formed. Has been realized.
  • the optical axis adjustment is very high. That is, the required accuracy of the optical axis adjustment is ⁇ 10 / rad or less. In other words, this angle range is equivalent to ⁇ lcm 1 km away. This is a value that easily moves due to temperature changes. If at least one part of the device requires such angular accuracy, the required accuracy for the entire device will result in this value.
  • the present invention solves the above-mentioned conventional problems, and is a portable, compact, and inexpensive laser beam having a pulse width that is extremely narrow, for example, 100 femtoseconds. It is intended to provide a novel laser device mounted in a single housing, which can output light from an optical fiber without expanding a pulse width. Disclosure of the invention
  • a laser device is a laser device including a laser oscillator, a group velocity dispersion control unit, and a transmission unit, and has a unique configuration as described below. That is, a laser oscillator, a group velocity dispersion control unit that controls group velocity dispersion of light output from the laser oscillator, and a part of a transmission unit that transmits light output from the group velocity dispersion control unit have the same casing. It is configured as a small, portable, new laser device housed in a portable device.
  • the laser oscillator generates pulsed light.
  • the group velocity dispersion controller controls the group velocity dispersion of the pulse light output from the laser oscillator.
  • the transmission unit must be at least a collimator and an optical fiber such as a single-mode fiber (hereinafter, also referred to as SMF) or a polarization maintaining fiber (hereinafter, also referred to as PMF). It is configured to transmit pulsed light whose group velocity dispersion is controlled by the group velocity dispersion controller.
  • One example is a laser oscillator, a group velocity dispersion control unit, and one end of a transmission unit, and a force; Thus, the non-fixed portion of the transmission section is led out of the housing.
  • the laser oscillator, the group velocity dispersion control unit, and one end of the transmission unit are fixed on one common support.
  • the optical axis adjustment between each optical unit has already been completed.
  • Each of these optical units is housed in a single housing together with the support. Therefore, each optical unit is provided in a single package (integrated). According to such an integrated structure, the temperature environment of each optical unit is shared. Moreover, there is no need to arrange each optical unit on an optical bench and adjust the optical axis. The user does not need to adjust the optical axis again, and can use short pulse light without pulse spread immediately.
  • the transmission unit includes a collimator, and an optical fiber is connected to the collimator, and the collimator controls the group velocity dispersion control. It is good to fix on the support in a state where it is aligned with the optical axis of the part.
  • the pulsed light output from the group velocity dispersion control unit is introduced into the optical fiber via a collimator, and is led out of the housing.
  • the signal is output from the terminal of the optical fiber as a part of the transmitting unit.
  • the positional relationship of each component in each of the laser oscillator, the group velocity dispersion control unit, and the transmission unit does not change due to the influence of heat. It is preferable that the relative positional relationship among the oscillator, the group velocity dispersion control unit, and the transmission unit is not changed by the influence of heat.
  • One method is to use a material with a low coefficient of thermal expansion, such as Zerodur (trade name of Shott), as a support.
  • stainless steel has a smaller coefficient of thermal expansion and is less susceptible to aluminum than aluminum, but its thermal conductivity is not as good as aluminum. This characteristic of stainless steel tends to cause non-uniform heat distribution, so that mechanical distortion is likely to occur throughout.
  • Aluminum is lightweight and has high thermal conductivity, so that heat is easily spread over the entirety, and partial thermal expansion does not occur. Therefore, deformation of the support is suppressed.
  • a water passage for flowing cooling water is preferably provided inside the support.
  • the heat radiation action of the support itself is promoted, and heat accumulation inside the support is suppressed.
  • the support is provided inside the housing, and the non-fixed portion of the transmission unit is led out of the housing.
  • the transmission section has a connection section detachably provided on a part of the housing, and an optical fiber as a part of the transmission section may be connected to the connection section. good.
  • the optical unit such as the laser oscillator and the group velocity dispersion controller is protected from the outside.
  • the support is connected to the housing via a buffer.
  • the main part of the buffer is, for example, a vibration absorber made of a substance using a silicone rubber-based material, for example, a gel-like substance.
  • the shock absorber may be a shock absorber and a housing which can at least significantly reduce the transmission of vibration and shock from the outside of the housing to the support.
  • At least one of the body and the support is provided with a fixing portion capable of fixing a buffer, and the buffer is made of silicone rubber.
  • the above-mentioned fixing portion having a screw portion capable of fixing the buffer to the support or the housing is molded integrally with the buffer, and the seal is provided between the support and the housing.
  • the laser oscillator is a mode-locked solid-state laser, for example, a mode-locked titanium sapphire laser.
  • an excitation light source for supplying excitation light to the laser oscillator is further provided.
  • the excitation light source is preferably a diode-excited solid-state laser.
  • the laser device of the present invention preferably, at least a support portion (except for a screw portion) for fixedly supporting an optical system constituting a laser oscillator, a group velocity dispersion control portion and a transmission portion is provided. It is preferable that the same material as that of the support is used for the main part. According to such a configuration, even when subjected to a thermal cycle, the difference in thermal expansion between components does not accumulate. Therefore, the optical path does not deviate. Also, in the laser device of the present invention, it is preferable that the laser device, the group velocity dispersion control unit, and the force support be mounted on the front and back of the force support, respectively.
  • the miniaturization reduces the non-uniform temperature distribution of the entire apparatus. Even if a slight non-uniform temperature distribution remains, the difference between the effects of heat on the front and back of the support is reduced, and the resulting optical path shift is less likely to occur. In addition, the miniaturization reduces the absolute value of expansion and contraction due to thermal expansion.
  • a pulse light output from a laser oscillator mounted on one side of the support is applied to a laser beam provided on the support. It is preferable to supply through a through hole to the group velocity dispersion control unit mounted on the other side of the support.
  • the light beam is stable.
  • the group velocity dispersion control unit preferably includes a diffraction grating, a first reflector, and a second reflector.
  • the diffraction grating described above diffracts each wavelength component of the pulsed light supplied from the laser oscillator in a direction corresponding to the wavelength.
  • the first reflector reflects the pulsed light incident through the diffraction grating in a direction parallel to the incident direction of the pulsed light and returns the reflected light to the diffraction grating.
  • the second reflector reflects the pulsed light incident through the first reflector and the diffraction grating in a direction parallel to the incident direction of the pulsed light and returns the reflected light to the diffraction grating.
  • the pulsed light supplied from the laser oscillator enters the diffraction grating.
  • Each wavelength component of the pulsed light is diffracted in a direction corresponding to the wavelength.
  • Each wavelength component of the pulsed light enters the first reflector disposed at a predetermined position, and is reflected in a direction parallel to the incident direction, so that it is returned to the diffraction grating.
  • the pulsed light is diffracted by the diffraction grating toward the second reflector.
  • the second reflector reflects each wavelength component of the pulsed light in a direction parallel to the incident direction. Therefore, the pulsed light is returned to the diffraction grating. Thereafter, the pulsed light is propagated through the optical path parallel to the outward path in the order of the diffraction grating, the first reflector, and the diffraction grating.
  • an optical path difference occurs between the wavelength components of the pulsed light according to the distance between the diffraction grating and the first reflector.
  • a long wavelength component propagates along a longer optical path than a short wavelength component. Therefore, when the pulsed light passes through this group velocity dispersion control unit, it undergoes negative group velocity dispersion, and relatively near the rear end of the pulse becomes a shifted component on the long wavelength side, and near the front end of the pulse is short. This is the component shifted on the wavelength side. Since this pulse light is introduced into the optical fiber of the transmission section, the pulse light receives positive group velocity dispersion in the transmission section and is output from the optical fiber of the transmission section.
  • a drive mechanism for moving the first reflector is provided so that the distance between the first reflector and the diffraction grating can be varied.
  • a moving mechanism is provided that can move the first reflector in a linear direction along the optical axis.
  • each of the first and second reflectors is a prism having two reflection surfaces perpendicular to each other, and the first and second reflectors serve as the first reflector.
  • the first and second reflections are such that the surface perpendicular to both of the two reflection surfaces of the prism and the surface perpendicular to both of the two reflection surfaces of the prism as the second reflector are perpendicular to each other. Place your body.
  • negative feedback is performed using the pulse width of the pulse light output from the transmission unit as an index for controlling the moving mechanism of the first reflector.
  • the position of the first reflector can be adjusted so that the pulse width of the pulse light output from the transmission unit is further reduced.
  • the angle of the diffraction grating with respect to the incident pulse light can be changed using the wavelength of the pulse light output from the laser oscillator as an index. And good.
  • the angle of the diffraction grating with respect to the incident pulse light is set so that the beam passes through the optimal position of the beam path of the first reflector and the second reflector. Automatically Can be adjusted. Therefore, even if the wavelength of the pulse light is changed, the pulse light that has passed through the group velocity dispersion control unit is supplied to the transmission unit at a constant intensity regardless of the wavelength, and the output of the transmission unit does not fluctuate.
  • a laser device can be provided.
  • the diffraction grating is rotated in accordance with the wavelength of the pulse light, it is not necessary to re-align the group velocity dispersion control unit even if the wavelength of the pulse light changes.
  • a positioning projection or a depression is provided on a side of the laser oscillator, the group velocity dispersion control unit, and the component constituting the transmission unit connected to the support. It is preferable that a concave portion or a convex portion which can be combined with the convex portion or the concave portion is formed at a predetermined position of the support.
  • the position where the component including the optical element and the holder can be arranged is limited to a predetermined position provided with the concave portion or the convex portion on the support body side.
  • These concave portions or convex portions on the support side and convex portions or concave portions on the component side can be formed with high dimensional accuracy and positional accuracy, respectively, by making full use of current machining technology. Therefore, simply placing the component on the support so that the convex or concave portion on the component side is combined with the concave or convex portion on the support side, it is possible to precisely place the component at a predetermined position on the support. it can.
  • the optical element of the component is slightly deviated from the optical axis, this axis deviation can be corrected by the optical element fine movement mechanism generally included in the holder constituting the component. Therefore, according to this configuration, the work of adjusting the axis of the optical element can be greatly reduced as compared with the related art, and the desired optical system can be formed more easily than before.
  • the position of the laser beam of the laser oscillator can be suppressed to a fixed height of 18 mm or less from the surface of the support.
  • a groove is formed in the support, and the concave and convex portions are provided in the groove to dispose the optical element and the holder, and the laser beam is also allowed to pass through the groove in the support. Can be.
  • a compression unit using a semiconductor crystal having positive group velocity dispersion is further coupled to an end of the non-fixed portion of the transmission unit.
  • a sufficiently weak femtosecond pulse of about 1 millimeter can be transmitted by a fiber.
  • a weak intensity is unsuitable for the application of femtosecond pulses. It is necessary to transmit at least 50 millimeters at least.
  • the compression unit can be used together with the group velocity dispersion control unit.
  • the group velocity dispersion controller applies a negative group velocity dispersion to an optical pulse, thereby expanding an optical pulse of, for example, about 100 femtoseconds to about 6 picoseconds. .
  • an optical pulse of, for example, about 100 femtoseconds to about 6 picoseconds.
  • the pulse width is about 3 picoseconds, and has not returned to femtoseconds. Therefore, at the end of the fiber, the pulse width is compressed from picoseconds to femtoseconds at once at the fiber end by the above-mentioned compression unit.
  • This compression unit is made of a semiconductor crystal, and utilizes a steep positive dispersion curve at a band gap end of the crystal. Femtosecond pulsed light with a high average intensity cannot be transmitted only by a fiber. However, as described above, the pulse width is extended to picoseconds by the group velocity dispersion control unit, transmitted while maintaining the average intensity by the transmission unit, and finally, the pulse width is increased by using the compression unit. The compression enables fiber transmission of femtosecond pulsed light.
  • the dimensions of the housing are set to a length of 6 mm. It can be mounted at a height of 506 mm or less, a height of 508 mm or less, a width of 234 mm or less, and a weight of 5 O kg or less.
  • the group velocity dispersion control unit has an acousto-optic element and at least two reflectors, and the incident light incident on the acousto-optic element is: After passing through the acousto-optic element, it proceeds to the first reflector, which is one of the two reflectors, and is reflected there.Then, the light passes through the acousto-optic element and is reflected by the two reflectors.
  • the light goes to a second reflector, which is the other reflector of the plate, is reflected there, and travels in the optical path of the incident light in the opposite direction, from the acoustic optical element to the first reflector, the acoustic The acousto-optic element and at least two reflectors so that the light travels toward the optical element and exits in the opposite direction to the same optical path when entering the acoustic optical element And the acousto-optic element transmits incident light.
  • a quarter-wave plate may be provided between the second reflector and the acousto-optic element to rotate the polarization directions of the incident light and the reflected light by 90 degrees. By doing so, it is possible to reliably separate the light that enters and exits the group velocity dispersion control unit.
  • the laser light output from the laser oscillator is linearly polarized light
  • the transmission unit has at least two quarter-wave plates. And at least one optical fiber.
  • the linearly polarized laser light incident on the transmission section is one of the two quarter-wave plates. (Hereinafter also referred to as a first quarter-wave plate), is converted into circularly polarized light, passes through the collimator, and enters the input side of the optical fiber. The light enters the end and is transmitted through the optical fiber ⁇ .
  • a quarter-wave plate different from the first quarter-wave plate hereinafter referred to as a second quarter-wave plate
  • Also referred to as a one-wave plate.
  • the portion near the output side end of the optical fiber may have a structure in which the core diameter gradually increases over a length of 1 mm or more.
  • the laser device of the present invention preferably has a light detection device for detecting a mode synchronous oscillation state, and when the mode synchronous oscillation is stopped, the laser device responds to a detection signal of the light detection device. It is preferable to have a function of driving a driving mechanism for moving at least one of the mirrors constituting the laser oscillator and starting mode synchronous oscillation.
  • FIG. 1 is a diagram showing a configuration of a laser device according to an embodiment.
  • (A) is a diagram of the laser device as viewed from above, and
  • (B) is a diagram of the laser device as viewed from the side.
  • FIG. 2 is a diagram showing the configuration of the housing, (A) is a side view, and (B) is a front view.
  • FIG. 3 is a diagram showing a state of coupling between the support and the housing.
  • FIG. 4 is a diagram showing a configuration of a support.
  • FIG. 5 is a diagram showing a configuration of a laser oscillator.
  • FIG. 6 is a diagram showing a configuration of a group velocity dispersion control unit.
  • FIG. 7 is a view showing an example of a positioning mechanism.
  • A is a view of the optical element holder viewed from below, and
  • B is a view showing a part of the main surface of the support plate.
  • FIG. 8 is a diagram showing a configuration of another group velocity dispersion control unit.
  • FIG. 9 is a diagram illustrating an example in which a quarter-wave plate is used on the input side and the output side of the optical fiber of the transmission unit.
  • FIG. 1 is a diagram showing a configuration of a laser device according to an embodiment of the present invention.
  • Fig. 1 (A) shows the laser device viewed from above
  • Fig. 1 (B) shows the laser device viewed from the side (left side of Fig. 1 (A)). ing.
  • This laser device mainly includes a laser oscillator 10, a group velocity dispersion control unit 12, and a transmission unit 14.
  • the laser oscillator 10 is composed of an optical unit that generates pulsed light.
  • the group velocity dispersion controller 12 is an optical unit that controls the group velocity dispersion of the pulse light output from the laser oscillator 10.
  • the transmission unit 14 includes at least a collimator 80 and an SMF 14 a as an optical fin, and the group velocity dispersion control unit 12 controls the group velocity dispersion. This is an optical unit for transmitting the pulsed light.
  • the laser oscillator 10 the group velocity dispersion control unit 12, one end of the transmission unit 14 and the force; one support plate 16 as a support Fixed on top.
  • the support plate 16 is an aluminum (aluminum 505 2) plate having a thickness of about 5 cm.
  • a laser oscillator 10 and a group velocity dispersion controller 12 are provided on each of the front and back sides of the support plate 16. That is, the laser oscillator 10 and the group velocity dispersion control unit 12 are installed so as to face each other with the support plate 16 interposed therebetween.
  • the transmission section 14 is composed of an SMF 14a and a collimator 80 connected to the end thereof, and the SMF 14a and the collimator 80 are sufficiently connected. Are connected to each other with their relative positions adjusted with high precision.
  • One end of the transmission unit 14, that is, the collimator 80 is connected to the optical axis of the group velocity dispersion control unit 12.
  • the group velocity dispersion control of the support plate 16 1 It is fixed on the two sides. Therefore, the pulse light output from the group velocity dispersion controller 12 is introduced into the SMF 14a via the collimator 80.
  • the size of the support plate 16 can be reduced as compared with a case where each optical unit is provided on one surface of the support plate 16. Therefore, the size of the entire device is reduced, and the weight is reduced. Moreover, only one side of the support plate 16 is not affected by the weight of the optical unit or by the heat released from the optical unit, and is not affected by partial gravity. The risk of optical axis misalignment of the optical unit due to thermal expansion is reduced.
  • the laser device mounted in one case in this example has a length of 600 mm, a height of 500 mm, and a thickness of 200 mm. Weight is less than 50 kg.
  • FIG. 2 is a diagram showing a configuration of a B-body.
  • FIG. 2 (A) is a side view
  • FIG. 2 (B) is a front view.
  • FIG. 2 (A) shows the group velocity dispersion control unit 12 side of the support plate 16.
  • the weight of the laser device of this embodiment is about 5 OK g. With such a weight, it is necessary to consider the safety of transportation and the distortion of the housing due to the weight. Therefore, as shown in FIG. 2 (A), for the case 18, two plates 20 and 22 are opposed to each other in parallel, and there are four thick aluminum plates between them. The one connected by pipe 24 is used. The outer diameter of the pipe 24 is about 30 mm. The strength against is secured. The pipe 24 is provided with an appropriate anti-slip process, for example, a groove process as shown in the figure in consideration of gripping by hand. A support plate 16 provided with an optical unit is accommodated between the pipes 24. As shown in FIG. 2 (B), the support plate 16 is provided so that the main surface (the surface on which the optical unit is provided) extends vertically in FIG. 2 (B). Can be
  • the support plate 16 including the optical unit is covered by the outer plate 26.
  • the laser device of this embodiment is element-free.
  • one plate 20 is provided with a hole for passing SMF14a. The non-fixed portion of SMF14a is led out of B-body 18 through this hole.
  • a connector capable of connecting the SMF 14 a is provided on the board 20, and the light output from the group velocity dispersion controller 12 is transmitted to this connector via the collimator 80. If this is done, the SMF 14a can be attached and detached in this area.
  • this connector is incorporated with the collimator 80 and is provided on the plate 20 as a connector. If necessary, an optical fiber such as an SMF 14a may be connected. can do.
  • the SMF14a used in this example has a core diameter of 5.3 / m and a numerical aperture N A of 0.12.
  • the laser device of this embodiment includes an excitation light source 28 for supplying excitation light to the laser oscillator 10.
  • the excitation light source 28 is fixedly installed above the support plate 16 (the upper part in FIG. 2 (A)).
  • FIG. 3 shows a cross section taken along the line I-I of FIG. 2B including the support plate 16.
  • FIG. 3 is a cross-sectional view showing a state of coupling between the support and the housing.
  • a bridge plate 30 is provided below the support plate 16 (the lower side in FIG. 3), and both ends of the bridge plate 30 are connected to the plates 20 and 22, respectively.
  • An appropriate number of vibration absorbers 32 made of, for example, a gel-like substance are provided on the cross-linking plate 30 as a buffer.
  • the support plate 16 is composed of these vibration absorbers 3 2 Is linked to the B-body through Also, both the plates 20 and 22 facing the side surface of the support plate 16 are provided with an appropriate number of vibration absorbers 32. Therefore, the side of the support plate 16 is also connected to the housing via the vibration absorber 32. Further, an appropriate number of vibration absorbers are also provided on the back side of the exterior plate 26 facing the main surface of the support plate 16.
  • the support plate 16 is provided in the housing 18 with the vibration absorber 32 interposed therebetween, thereby realizing a predetermined vibration-proof structure. Therefore, there is no need to install it on a vibration isolation table.
  • vibration absorbers with a diameter of 30 mm, a height of 22 mm, and a resonance point near 10 Hz below the support plate 16, one each in front, rear, left and right, a total of 1 It is preferable to arrange two.
  • the vibration absorber 32 has been described as an example of a shock absorber, the vibration absorber as a shock absorber is used as a shock absorber to enhance vibration resistance.
  • the shock absorber is configured to have a shock absorber that can greatly reduce the transmission, and a fixing part that can fix the shock absorber to at least one of the housing and the support. It is preferable to use silicone rubber cushioning material.
  • the fixing portion has a structure having a screw portion capable of fixing the buffer to a support or a housing, and the two fixing portions are molded integrally with the buffer to form a support and a housing.
  • the silicone rubber cushioning part is interposed between the two parts, and the screws of the two fixed parts are inserted into the holes provided in the support and the housing, respectively, and tightened with nuts.
  • the holes provided in the support and the housing are formed to have an inner diameter larger than the diameter of the screw, it is convenient for fixing.
  • FIG. 4 is a plan view showing the configuration of the support plate 16.
  • FIG. 4 shows the side on which the group velocity dispersion control unit 12 is provided.
  • An excitation light source 28 is provided above the support plate 16.
  • the support plate 16 is formed of aluminum (Al A minimum alloy may be used. ). Each optical element is installed at the part 16a, 16b and 16c where the surface of the aluminum plate is excavated. These 16a, 16b, and 16c are concave portions, and their shapes can be reduced in weight while maintaining strength.
  • a hole through which cooling water passes is formed in the center of the thickness of the plate as a water channel.
  • a bendable hollow pipe 34 is connected to the hole, through which cooling water is supplied into the support plate 16.
  • a green laser described below which is used as an excitation source, usually starts in about 20 minutes.
  • the temperature usually rises to about 29 degrees C at the front of the green laser housing and about 27 degrees C at the rear.
  • This temperature difference causes thermal expansion of aluminum.
  • the magnitude of the strain reaches a maximum of about 20 ⁇ m at a temperature difference of 2 ° C.
  • the displacement of the housing which is expected to be 20 ⁇ in value, poses almost no problem when the green laser is used alone, but when integrated, the optical axis accuracy of the optical system including the green laser and the titanium sapphire laser described later In order to keep the temperature below 1 ⁇ ⁇ , the temperature distribution in the housing of the green laser cannot be ignored.
  • a 10-mm-thick aluminum plate with a water-cooling mechanism was placed in the middle part connecting the green laser housing and the titanium sapphire resonator.
  • Water cooling was performed by making four through holes in the aluminum plate and passing circulating cooling water through the holes.
  • the cooling water temperature is about 23 degrees and the flow rate is about 600 milliliters per minute.
  • a 1 Omm thick aluminum plate having a water cooling mechanism provided at an intermediate portion connecting the green laser housing and the titanium sapphire resonator was connected to the support plate 1. It is more preferable to be formed integrally with 6 in order to achieve the object of the present invention such as reduction in size and weight.
  • titanium sapphire resonators have five through holes in the center of the support where the resonators are located, and the circulating water from another cooler passes inside. cold The temperature of the water is about 23 degrees (:, the flow rate is about 600 milliliters per minute.
  • a bypass is provided in the middle of the circulation of the cooling water of the support to cool the exhaust heat side of the Peltier element that cools the titanium sapphire crystal.
  • the surface temperature of the green laser and the titanium sapphire resonator is about 24 ° C. over the entire surface of the green laser, and the surface temperature of the titanium sapphire resonator is about 23 ° C. .
  • each optical element is installed on the excavated portion of the support plate 16 on the laser oscillator 10 side.
  • the excitation light output from the excitation light source 28 is reflected by the excitation light introduction mirror 38 provided on the upper side surface of the support plate 16 and propagated to the laser oscillator 10 side. It has become.
  • FIG. 5 is a block diagram showing a configuration of the laser oscillator 10.
  • This laser oscillator 10 is configured as a mode-synchronous titanium sapphire laser.
  • the size of the laser oscillator 10 in this example has a width of 320 mm, a length of 0.590 mm, and a height force of 90 mm.
  • a diode-excited solid-state green laser is used as the above-mentioned excitation light source 28.
  • the diode inside the excitation light source 28 is driven by a dry cell 36.
  • the pump light source 28 outputs pump light having a wavelength of 532 nm and an output of 3.5 W.
  • the excitation light is sequentially reflected by the excitation light focusing mirrors 38 and 40 and transmitted to the laser oscillator 10.
  • the laser oscillator 10 includes a Ti: A1Oa crystal 42 as a laser medium.
  • the Ti: Al Oa crystal 42 is sapphire doped with 0.15% by weight of titanium.
  • T i: A 10 0 The emission spectrum of the i crystal is 600 ⁇ ⁇ ! Over the wavelength range of ⁇ 110 O nm.
  • This crystal 42 has a thermal electric cooler (hereinafter, abbreviated as ⁇ . Name. ) Is installed, and the temperature is controlled to a constant state.
  • This C. C is controlled by a T.E.C driver 44.
  • Chamber mirrors 46a to 46d constitute a general Z-shaped resonator.
  • the light in the resonator is reflected seven times between these chirp mirrors 46a to 46d, and then is output to the outside via an output mirror 48. In this way, by repeatedly reflecting light between the channel mirrors 46a to 46d, the group velocity dispersion of the Ti: A120 : i crystal 42 is compensated. I have.
  • a terminating mirror 50 is provided at one end of the resonator of the laser oscillator 10.
  • the terminal mirror 50 can be moved in the optical axis direction by a slider mechanism.
  • the slider mechanism is driven by a solenoid 54 controlled by a starter 52.
  • the starter 52 is activated by a manually operated switch. Then, the starter 52 operates the solenoid 54 to move the terminal mirror 50 minutely. As a result, FM modulation occurs in the resonator, and mode synchronization starts.
  • Excitation light incident on the laser oscillator 10 passes through a wave plate (Eno 2 plate) 53 and is then condensed by the excitation light condensing lens 55 on the Ti: A 12 ⁇ crystal 42.
  • the light reflected by the chirp mirror 46a is the chirp mirror 46b, the terminal mirror 50, the chirp mirror 46b, the chirp mirror 46a, and the concave mirror 56.
  • the output mirror 48 outputs an optical pulse of about 70 femtoseconds.
  • the maximum output of the laser oscillator 10 is 450 mW.
  • the laser oscillator 10 constantly monitors the mode synchronization state, and if the mode synchronization state stops, automatically, that is, as described above, regardless of the manual operation. Also has a function to drive the solenoid 54 to the mode and start the mode synchronization again. are doing.
  • the following principle is used for monitoring the mode synchronization status.
  • the output light When the mode-locked oscillation occurs, the output light generates a pulse train that repeats at a frequency determined by the optical path length of the resonator.
  • This repetition frequency is represented by c (2 L), where c is the light speed and L is the cavity length. That is, for a resonator length of 1.5 m (meter), the repetition frequency of the pulse train is 100 MHz (megahertz).
  • a photo diode 57 is provided inside the laser oscillator 10 as such a photodetector. The photo diode 57 receives the light transmitted through the concave mirror 56 described above. The signal received by the photodiode 55 is input to the starter 52.
  • the starter 52 can monitor the mode synchronization state based on the received signal of the photodiode 57. Specifically, the frequency of the received signal of the photodiode 57 is converted to about 1 to 10 by a counter. Then, the frequency-converted signal is guided to a charge pump circuit built in the starter 52.
  • This charge pump circuit is an electronic circuit in which the output voltage increases when a repetitive signal is input, and decreases when no repetitive signal is input. The output state of this circuit is used as a trigger signal sent to the solenoid 54.
  • a birefringent filter is inserted after the laser medium in the resonator.
  • the birefringent filter is a parallel plate formed of a birefringent medium, for example, quartz.
  • the incident surface of the birefringent filter is provided such that the incident angle with respect to the laser beam is one angle of the pre-ustor.
  • the wavelength of the laser beam in the resonator can be selected.
  • the pulse light output from the laser oscillator 10 is reflected by a mirror 16 provided on the laser oscillator 10 side of the support plate 16 and is opened from the front side to the back side of the support plate 16.
  • FIG. 6 is a block diagram showing the configuration of the group velocity dispersion control unit 12.
  • the group velocity dispersion controller 12 includes a right-angle prism 62 as a first reflector, a diffraction grating 64 and a right-angle prism 66 as a second reflector.
  • Ri the propagation path of light solid b and broken r.
  • the above-described diffraction grating 64 diffracts each wavelength component of the pulsed light supplied from the laser oscillator 10 in a direction corresponding to the wavelength.
  • the right-angle prism 62 reflects the pulse light incident through the diffraction grating 64 in a direction parallel to the incident direction of the pulse light and returns the reflected light to the diffraction grating 64.
  • the right-angle prism 66 reflects the pulse light incident through the right-angle prism 62 and the diffraction grating 64 in a direction parallel to the incident direction of the pulsed light, and returns the reflected light to the diffraction grating 64. It is.
  • Each of the right-angle prisms 62 and 66 has two reflecting surfaces perpendicular to each other.
  • the pulse light sent from the laser oscillator 10 is input to the group velocity dispersion controller 12 through the through hole 61 provided in the support plate 16.
  • the input pulse light is reflected in the order of the plane mirror 68, the convex mirror 70, the concave mirror 72, the plane mirror 74, the plane mirror 76, and the plane mirror 78 provided in the group velocity dispersion controller 12.
  • the pulse light reflected by the plane mirror 78 first enters the diffraction grating 64.
  • the pulse light that has entered the diffraction grating 64 is separated into each wavelength component, and each wavelength component is diffracted in a direction corresponding to the wavelength.
  • the long wavelength component light The path is indicated by a solid line r, and the optical path of the short wavelength component is indicated by a dashed line b.
  • the long wavelength component has a larger diffraction angle than the short wavelength component, and after diffraction, the long wavelength component r and the short wavelength component b do not match.
  • the pitch of the diffraction gratings 64 is 600 lines Z mm.
  • the size of the diffraction grating 64 is 30 mm in width and 30 mm in length.
  • the pulse light diffracted by the diffraction grating 64 enters the right-angle prism 62 and is reflected.
  • the pulsed light is sequentially reflected by two reflection surfaces perpendicular to each other in the right-angle prism 62, and the incident direction (when the pulsed light diffracted by the diffraction grating 64 enters the right-angle prism 62) Is reflected in a direction parallel to the propagation direction.
  • the reflected pulse light enters the diffraction grating 64 again.
  • the incident position of the pulsed light is different from the position where it is first incident on the diffraction grating 64, and also differs according to the wavelength component.
  • each wavelength component of the pulsed light is diffracted in the same direction as the incident direction (the propagation direction when the pulsed light reflected by the plane mirror 78 enters the diffraction grating 64).
  • the wavelength components are parallel to each other. Then, each wavelength component is incident on the right-angle prism 66.
  • the pulsed light is sequentially reflected by two reflecting surfaces perpendicular to each other in the right-angle prism 66, and is reflected in a direction parallel to the incident direction.
  • the reflected pulse light enters the diffraction grating 64 again.
  • a surface perpendicular to both of the two reflection surfaces of the right-angle prism 62 and a surface perpendicular to both the two reflection surfaces of the other right-angle prism 66 are arranged perpendicular to each other.
  • the surface perpendicular to both of the two reflecting surfaces of the right-angle prism 62 is a surface parallel to the paper surface in FIG.
  • the surface perpendicular to both of the two reflecting surfaces of the other right-angle prism 66 is a surface perpendicular to the paper surface in FIG.
  • the pulsed light is first reflected in a direction perpendicular to the plane of FIG. 6 and then reflected in a direction parallel to the plane of FIG. Will be returned. After that, the pulsed light is first propagated in the order of the plane mirror 78, the diffraction grating 64, the right-angle prism 62, the diffraction grating 64, and the right-angle prism 66. Is propagated in another optical path parallel to the optical path of the optical path. That is, the pulsed light propagates in the order of the diffraction grating 64, the right-angle prism 62, and the diffraction grating 64.
  • the return optical path from the diffraction grating 64 to the direction of a collimator 80 to be described later is shifted from the above-mentioned optical path in the direction perpendicular to the plane of the drawing. Go straight without being incident on 8.
  • the pulsed light is output from the group velocity dispersion control unit 12, enters the collimator 80 constituting the transmission unit 14, and receives the SMF 14 connected to the collimator 80. a, and transmitted outside the device by SMF 14a.
  • the right-angle prism 62 moves in a linear direction along the optical axis so that the distance between the right-angle prism 62 and the diffraction grating 64 can be varied. It has a moving mechanism that enables it. Because of this movement mechanism, the right-angle prism 62 can perform linear movement while keeping the incident direction of the pulse light on the right-angle prism 62 constant. That is, the right-angle prism 62 can move in the direction a shown in FIG. When the right-angle prism 62 is moved, the distance between the right-angle prism 62 and the diffraction grating 64 changes, so that the optical path difference between the wavelength components of the pulsed light can be changed.
  • the right-angle prism is used for the first and second reflectors, there is an advantage that, unlike the advantage of the roof-type mirror, the adjustment is extremely easy as compared with the case of using the roof-type mirror. is there.
  • the long wavelength component r propagates along a longer optical path than the short wavelength component b. Therefore,
  • the group velocity dispersion controller 12 gives negative group velocity dispersion to the pulsed light.
  • the pulse width of a pulse light of about 100 fs can be extended to about 6 ps.
  • the output of the pulsed light at the time of passing through the diffraction grating 64 is 110 mW, but if the pulse width is as described above, a pulse of several hundred milliwatts will be obtained. It is possible to transmit optical signals by SMF 14a ignoring the self-phase modulation effect.
  • a compression unit 82 is connected to the output end (the end of the non-fixed portion) of the SMF 14a.
  • the compression unit 82 is made of a semiconductor crystal having a positive group velocity dispersion. Such crystals include, for example, ZnSe and CaSe.
  • the compression unit 82 compresses an optical pulse width of about picoseconds to about femtoseconds using a steep positive dispersion curve at the band gap end of the semiconductor crystal.
  • the pulse width of the pulse light is about 3 picoseconds at the output end of SMF14a.
  • the group velocity dispersion control unit 12 of this embodiment employs an optical system in which a beam is spatially folded. For this reason, it can be formed in a plane having a size of about 2 as compared with a conventional apparatus using a prism pair or a diffraction grating pair.
  • the right-angle prism 62 can be slid by a distance of 6 O mm.
  • the group velocity variance of the group velocity variance controller 12 can be changed in the range of 1500 000 fs to 200 000 fs.
  • the length of the connectable SMF14a is calculated from this value, it becomes 5 m from 3.5 m force. Since an SMF 14a having such a length can be used, the laser device of this embodiment can be used, for example, as a light source for a microscope, a light source for two-photon absorption lithography, or a light source for optical communication. It is practically possible to use it.
  • the right-angle prism 62 emits light from the diffraction grating 64 into the right-angle prism 62 so that the distance between the right-angle prism 62 and the diffraction grating 64 can be changed.
  • the center wavelength of the light emitted from the diffraction grating 64 is directed in the direction of the optical axis of the light. Line movement is possible.
  • the length of the diffraction grating 64 in the direction perpendicular to the direction of the groove is preferably 50 mm or more.
  • the group velocity dispersion inside the group velocity dispersion controller 12 can be adjusted according to the length of the SMF 14a. Therefore, there is no need to redo the alignment when the SMF 14a is replaced.
  • the pulse of the pulse light output from the SMF 14a is required for controlling the moving mechanism of the right-angle prism 62.
  • the width is detected, the difference between the detected pulse width and the target pulse width is calculated, and the movement amount of the right-angle prism 62 is negatively fed back to the moving mechanism of the right-angle prism 62. It is. As a result, the pulse width output from SMF14a becomes constant.
  • the diffraction grating 64 is configured to be rotatable about an axis parallel to the grating plane (an axis perpendicular to the paper surface in FIG. 6). Then, the angle of the diffraction grating 64 with respect to the incident pulse light is changed using the wavelength of the pulse light output from the laser oscillator 10 as an index. That is, the diffraction grating 64 is rotated in accordance with the rotation angle of the birefringent medium constituting the wavelength variable mechanism in cooperation with the wavelength variable mechanism of the laser oscillator 10 described above. As described above, since the diffraction grating 64 is rotated in accordance with the wavelength of the pulse light, there is no need to repeat the alignment even if the wavelength of the pulse light changes.
  • the laser device according to the present embodiment is configured so that three functionally different units are combined to function as one device.
  • This laser device handles a laser beam propagating in space.
  • This section describes the design and manufacturing contrivances for such a space beam.
  • a positioning projection or a depression is provided on the side of each of the components constituting the laser oscillator 10, the group velocity dispersion control unit 12 and the transmission unit 14 connected to the support plate 16. is there. Then, concave portions or convex portions in which these convex portions or concave portions are combined are formed at predetermined positions on the support plate 16. Both the optical unit and the support plate 16 are provided with such a positioning mechanism.
  • FIG. 7 is a perspective view showing an example of a positioning mechanism.
  • FIG. 7 (A) shows the optical element holder 84 as viewed from below.
  • FIG. 7 (B) shows a part of one main surface of the support plate 16.
  • the optical element holder 84 is for holding an optical element constituting the above-mentioned optical unit.
  • a concave portion 88 in which the convex portion 86 of the optical element holder 84 is fitted is formed at a predetermined position of the support plate 16. Therefore, the optical element can be arranged at a predetermined position on the support plate 16 by fitting the convex portion 86 of the optical element holder 84 into the concave portion 88 on the support plate 16. . Thereafter, the optical element holder 84 may be fixed to the support plate 16 by a required means.
  • the optical element holder 84 is arranged at a predetermined position by providing the concave portion 88 of the support plate 16.
  • the concave portion 88 of the support plate 16 and the convex portion 86 of the optical element holder 84 can be formed with high precision by making full use of current machining technology. Therefore, the optical element is supported only by placing the optical element holder 84 on the support plate 16 so that the convex portion 86 of the optical element holder 84 is combined with the concave portion 88 of the support plate 16. It can be placed at a predetermined position on the plate 16 with high accuracy.
  • this axis deviation can be corrected by the optical element fine movement mechanism that the optical element holder 84 generally has. Therefore, according to this configuration, the axis adjustment work of the optical element can be performed. Since it can be reduced, a desired optical system can be formed more easily than before.
  • the material of at least the main part of the support part (excluding the screw part) for fixing the optical system constituting the laser oscillator 10, the group velocity dispersion control part 12 and the transmission part 14 is thus, the same aluminum as the support plate 16 is used. In this way, if the thermal expansion coefficients of the components are the same, the difference in thermal expansion between the components does not accumulate even when subjected to a thermal cycle, and the optical path shift is less likely to occur. .
  • the springs and rails of the parts to be finely adjusted should be made of stainless steel, and the mounting screws of the parts that need to be replaced should be straightened.
  • the height of the beam inside this laser device is unified to 18 mm except for a part of the group velocity dispersion control unit 12. This value is determined based on the standard number of the JIS-Z8801 industry standard as described below. In other words, commercially available standard lenses and mirrors are frequently used in terms of availability and cost. These standard products are often 1/2 inch (12.7 mm) in size. Therefore, considering the minimum required thickness of the mechanism to hold the optical element and its diameter as the height of the beam from the floor, it is most appropriate for the above dimensions. You have selected a value of 18 mm.
  • the possibility of downsizing the laser device of this embodiment will be described.
  • the diameter of such an optical element is often 1 to 2 inches. Therefore, if this diameter can be further reduced by half, the beam height can be further reduced from 18 mm. Furthermore, the size of the mechanical parts required for mounting the optical element can be reduced.
  • Reducing the beam height to 18 mm or less as described above depends on the influence of heat and gravity when the support exemplified in the support plate 16 is mounted vertically on the housing.
  • the risk of deviation in the optical path can be reduced.
  • a groove is provided in the support plate 16 and each optical system is configured and arranged so that the inside of the groove serves as an optical path, the risk of optical path shift is further reduced.
  • the current laser device has a maximum length, height, and width of the housing of 6556 mm, height of 508 mm, and width of 23.4 mm.
  • the weight is reduced to 50 kg or less.
  • the miniaturized embodiments are not limited to those that are commercially available as standard products, and the size of the prox is halved by using optical elements with original dimensions. it can.
  • the support of the resonator is less than 200 mm in width, less than 550 mm in length, and less than 60 mm in thickness.
  • the excitation light source 28 has a width of 10 Omm or less, a length of 3900 mm or less, and a height of 90 mm or less by the same method.
  • the overall dimensions of the laser device can be reduced to a maximum length of the housing of not more than 620 mm, a height of not more than 430 mm and a width of not more than 170 mm.
  • the size of the block can be further reduced by increasing its packing density without reducing it.
  • the resonator is less than 60 mm in width, less than 105 mm in length and less than 45 mm in height.
  • the excitation light source 28 has a width of 3 Omm or less, a length of 6 Omm or less, and a height of 3 Omm or less.
  • the dimensions of the entire laser device can be reduced to a length of 23 O mm or less, a height of 1775 mm or less, and a thickness of 150 mm or less.
  • FIG. 8 is a diagram illustrating another example of the group velocity dispersion control unit 12.
  • reference numeral 100 denotes incident light
  • 101 denotes an acousto-optic element having a drive unit 102
  • 103 denotes a first reflector
  • 104 denotes a second reflector
  • 105 denotes 4 A one-half wavelength plate
  • 106 is an input / output separation element
  • 107 is an optical path of output light
  • 108 is a collimator
  • 109 is an optical fiber
  • 110 to 113 are optical paths. is there.
  • the acousto-optic device 101, the first reflector 103, the second reflector 104, and the quarter-wave plate 105 are components of the group velocity dispersion controller 12.
  • the collimator 108 and the optical fiber 109 form a part of the transmission unit 14.
  • the incident light 100 incident on the group velocity dispersion control unit 12 travels through the input / output separation element 106 to the optical path 110, where the acoustic optical element 1 capable of transmitting the incident light is transmitted. It is incident on 0 1. If a suitable electric signal is input to the drive unit 102 of the acousto-optic device 101 to generate a traveling wave in the acousto-optic device 101, the incident light will change according to the wavelength as shown in the optical path 111.
  • the light is reflected by the first reflector 103, passes through the optical path 111, passes through the acousto-optic element 101 again, travels to the optical path 113, and is polarized by the quarter-wave plate 105.
  • the light is reflected by the second reflector 104, and again with the polarization plane rotated 45 degrees by the quarter-wave plate 105, the optical paths 113,
  • the light proceeds to 112, 111, 110 and enters the input / output separation element 106.
  • the light reflected by the second reflector 104 passes through the acousto-optic element 101, is reflected by the first reflector 103, and passes through the acousto-optic element 101.
  • the incident light 100 is output to a different optical path 106, enters the collimator 108 forming the transmission unit 14, and is transmitted through the optical fiber 109.
  • the second reflector 104 uses a right-angle prism having two reflecting surfaces, for example, as the second reflector 104. If the plane perpendicular to the reflecting surface is arranged, for example, perpendicular to the plane of the drawing, the light traveling along the optical path 113 and entering the prism as the second reflecting plate 104 will be, for example, The optical path is parallel to the optical path 1 1 3 and is perpendicular to the optical path 1 1 3 with respect to the plane of the drawing. The light travels through an optical path positioned vertically upward in the drawing.
  • the light reflected by the second reflector 104 passes through the acousto-optic element 101, is reflected by the first reflector 103, and passes through the acousto-optic element 101.
  • the input light and the output light pass through completely different positions in the height direction of the paper surface, so that the input / output separation element 106 is not necessarily required. What is necessary is just to arrange in the position parallel to 0.
  • FIG. 9 is a diagram for explaining an example of further improvement in the transmission unit 14.
  • reference numeral 120 denotes a quarter-wave plate
  • 122 denotes a lens
  • 122 denotes an input terminal of an optical fiber 123
  • 124 denotes an output terminal of an optical fiber 123
  • 1 25 is a quarter-wave plate
  • 126 and 127 are arrows indicating the traveling direction of light.
  • a linearly polarized pulsed laser beam incident on the transmission optical fiber 123 from the direction of arrow 126 is the first quarter-wave plate that is the laser wavelength one-to-four-wave plate.
  • the orientation of the first quarter-wave plate 1120 is adjusted so that the polarization state becomes circular polarization.
  • the laser beam having passed through the first quarter-wave plate 1 is condensed by a condenser lens 121 onto an input terminal 122 having a polished end surface of a single-mode optical fiber 123.
  • a condenser lens 121 Since the laser beam transmitted through the single-mode optical fiber 1 2 3 is circularly polarized, the electric field intensity per unit area is 1 ⁇ > ⁇ 2 compared to when it is linearly polarized. I have. Therefore, the limit of destruction of the optical fiber due to the intensity increases to twice the transmission average power.
  • the output terminal 1 2 4 of the optical fiber 1 2 3 has a core diameter that extends from several millimeters to several centimeters using TEC (Therma 1 1 y Expanded Core) technology. Have been.
  • the time width of the laser pulse becomes the shortest at the output end by expanding the diameter by 3.3 times
  • the area of the output surface becomes 3.3 times the square, that is, about 10 times. can do.
  • the strength per unit area at the output end of the optical fiber can be reduced to 1 to 10 and the breaking limit can be increased to about 10 times.
  • the laser pulse output from the output terminal 124 passes through the second quarter-wave plate.
  • the second quarter-wave plate 124 is adjusted so that circularly polarized light becomes linearly polarized light. Therefore, the output laser pulse from the second quarter-wave plate 125 is linearly polarized, and the pulse width is shortened by dispersion compensation as in the case of the laser output from the laser oscillator. Therefore, it has a high peak intensity and is in a linearly polarized state. Therefore, it is convenient when used in industrial fields such as biological science and lithography.
  • a lens that adjusts the output light to parallel light is installed on the output side of the output laser beam.
  • the quarter-wave plate 124 may be provided behind this lens.
  • the laser oscillator, the group velocity dispersion control unit, and one end of the transmission unit are fixed on a common support, and are mounted on one portable small casing.
  • the optical axis adjustment between the optical units constituting the laser device has already been completed, and the alignment is complete.
  • the present invention can freely cope with the case where the length of the output optical fiber of the transmission unit is changed according to the application or the wavelength to be used needs to be changed.
  • Each of these optical units and the support are housed in a common housing, and each optical unit is provided in a single package (integrated). With such an integrated structure, the temperature environment of each optical unit is standardized, or each optical unit is placed on an optical bench as in the past, and the user can control the optical axis. There is no need for adjustment, and short pulse light without pulse spread can be used immediately.
  • the laser device according to the present invention is portable, does not require difficult adjustment, and directly introduces ultrashort pulse light from an optical fiber to an object where the nonlinear optical effect functions effectively. It can be used as a light source for an optical one-optical router in optical communication, replacing a conventional laser diode. It can be used as a light source for lithography. Further, the present invention has a very wide applicability, as it can be used as a light source for a two-grating absorption microscope as another application.

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Abstract

Cette invention concerne un nouveau dispositif à laser comprenant un oscillateur laser, une unité de commande de dispersion de vitesse de groupe et une unité de transmission (tous organes logés dans le même boîtier), qui peut être utilisé pour diverses sources lumineuses, ne nécessite aucun réglage de l'axe optique et autorise l'émission de signaux via une fibre optique. L'oscillateur laser produit une lumière pulsée, l'unité de commande de dispersion de vitesse de groupe commande la dispersion de la vitesse de groupe des émissions de lumière pulsée provenant de l'oscillateur laser et l'unité de transmission, qui se compose d'au moins un collimateur et d'une fibre optique, transmet une lumière pulsée dont la dispersion de vitesse de groupe est commandée par l'unité de commande du même nom. L'oscillateur laser, l'unité de commande de dispersion de la vitesse de groupe et l'une des extrémité de la fibre sont fixées sur une seule et même feuille support. L'oscillateur laser et l'unité de commande de dispersion de la vitesse de groupe sont montés respectivement sur les surfaces avant et arrière de l'élément support. L'unité de commande de dispersion de vitesse de groupe peut faire appel à un laser en longueur d'onde variable ou à une fibre optique en longueur d'onde variable.
PCT/JP2000/004632 1999-07-12 2000-07-11 Dispositif a laser WO2001005003A1 (fr)

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JP2002368312A (ja) * 2001-06-06 2002-12-20 Kobe University 極短パルスレーザ
JP2007049090A (ja) * 2005-08-12 2007-02-22 Toshiba Corp レーザ発生器の冷却構造
JP2007535141A (ja) * 2004-03-31 2007-11-29 イムラ アメリカ インコーポレイテッド モジュール式ファイバ型チャープパルス増幅システム
WO2011027617A1 (fr) * 2009-09-01 2011-03-10 浜松ホトニクス株式会社 Appareil de conversion de la largeur d'impulsion et système d'amplification optique
JP2013131778A (ja) * 2013-03-29 2013-07-04 Hamamatsu Photonics Kk パルス幅変換装置および光増幅システム

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JP2006324601A (ja) * 2005-05-20 2006-11-30 Sunx Ltd レーザ装置及びレーザ加工装置

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5415758A (en) * 1977-07-06 1979-02-05 Nippon Telegr & Teleph Corp <Ntt> Production of optical fibers comprising provision of coupling parts
JPS57192080A (en) * 1981-05-21 1982-11-26 Fujitsu Ltd Semiconductor device
JPH05196887A (ja) * 1992-01-21 1993-08-06 Yokogawa Electric Corp 光パルス圧縮装置
JPH0688976A (ja) * 1992-09-07 1994-03-29 Kokusai Denshin Denwa Co Ltd <Kdd> 光パルス圧縮装置
JPH06152036A (ja) * 1992-11-13 1994-05-31 Semiconductor Energy Lab Co Ltd レーザー処理装置および処理方法
JPH08264869A (ja) * 1995-03-20 1996-10-11 Nippon Telegr & Teleph Corp <Ntt> 分散補正装置
JPH09260762A (ja) * 1996-03-25 1997-10-03 Hamamatsu Photonics Kk 超短パルスレーザ装置

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5415758A (en) * 1977-07-06 1979-02-05 Nippon Telegr & Teleph Corp <Ntt> Production of optical fibers comprising provision of coupling parts
JPS57192080A (en) * 1981-05-21 1982-11-26 Fujitsu Ltd Semiconductor device
JPH05196887A (ja) * 1992-01-21 1993-08-06 Yokogawa Electric Corp 光パルス圧縮装置
JPH0688976A (ja) * 1992-09-07 1994-03-29 Kokusai Denshin Denwa Co Ltd <Kdd> 光パルス圧縮装置
JPH06152036A (ja) * 1992-11-13 1994-05-31 Semiconductor Energy Lab Co Ltd レーザー処理装置および処理方法
JPH08264869A (ja) * 1995-03-20 1996-10-11 Nippon Telegr & Teleph Corp <Ntt> 分散補正装置
JPH09260762A (ja) * 1996-03-25 1997-10-03 Hamamatsu Photonics Kk 超短パルスレーザ装置

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
"Kougaku block IGO system; IGO system wo sasaeru shikake", OPTRONICS, no. 197, 1998, (JAPAN), pages 168 - 173, XP002946566 *
"Kougaku block IGO system; Object shikougata hikari kairo kouchiku shuhou", HIKARI ALLIANCE, vol. 9, no. 7, 1998, (JAPAN), pages 38 - 42, XP002946565 *
TAKUYA YODA ET AL: "Fiber delivery gata femt o byou titan sapphire laser system no kaihatsu", PROCEEDINGS OF THE 20TH ANNUAL MEETING, LASER GAKKAI (20P I 1), 20 January 2000 (2000-01-20), pages 34, XP002946567 *
W.H.LOH, ET AL: "Dispertion compensation over distances in excess of 500km for 10-Gb/s systems using chirped fiber gratings", IEEE PHOTONICS TECH. LETT., vol. 8, no. 7, 1996, pages 944 - 946, XP002932575 *

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002368312A (ja) * 2001-06-06 2002-12-20 Kobe University 極短パルスレーザ
JP2007535141A (ja) * 2004-03-31 2007-11-29 イムラ アメリカ インコーポレイテッド モジュール式ファイバ型チャープパルス増幅システム
JP2007049090A (ja) * 2005-08-12 2007-02-22 Toshiba Corp レーザ発生器の冷却構造
JP4602193B2 (ja) * 2005-08-12 2010-12-22 株式会社東芝 レーザ発生器の冷却構造
WO2011027617A1 (fr) * 2009-09-01 2011-03-10 浜松ホトニクス株式会社 Appareil de conversion de la largeur d'impulsion et système d'amplification optique
JP2011054737A (ja) * 2009-09-01 2011-03-17 Hamamatsu Photonics Kk パルス幅変換装置および光増幅システム
KR20120075458A (ko) * 2009-09-01 2012-07-06 하마마츠 포토닉스 가부시키가이샤 펄스폭 변환 장치 및 광 증폭 시스템
US8797641B2 (en) 2009-09-01 2014-08-05 Hamamatsu Photonics K.K. Pulse-width converting apparatus and optical amplifying system
KR101718177B1 (ko) 2009-09-01 2017-03-20 하마마츠 포토닉스 가부시키가이샤 펄스폭 변환 장치 및 광 증폭 시스템
JP2013131778A (ja) * 2013-03-29 2013-07-04 Hamamatsu Photonics Kk パルス幅変換装置および光増幅システム

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