Optical waveform measurement device, light irradiation device, laser processing device, observation device, optical waveform measurement method, light irradiation method, laser processing method, and observation method

Abstract

An optical waveform measurement device 1 comprises a light source 10, a waveform generation unit 20, a measurement unit 30, and a computation unit 40. On the basis of a light pulse outputted from the light source 10, the waveform generation unit 20 generates and outputs target light for which a time waveform is to be measured and a reference single light pulse. The target light and the reference single light pulse are inputted into the measurement unit 30 at a time interval that is longer than the time widths of the light. The measurement unit 30 is an autocorrelator and measures the shape of the autocorrelation of a time waveform for light that includes the target light and the reference single light pulse. The computation unit 40 finds a time waveform for the target light on the basis of the portion of the autocorrelation shape that represents the autocorrelation between a time waveform for the target light and a time waveform for the reference single light pulse. The present invention thereby provides a device and a method that make it possible to easily and accurately measure a time waveform for target light.

Description

Optical waveform measurement device, light irradiation device, laser processing device, observation device, optical waveform measurement method, light irradiation method, laser processing method, and observation method

[0001] The present disclosure relates to an optical waveform measurement device, a light irradiation device, a laser processing device, an observation device, an optical waveform measurement method, a light irradiation method, a laser processing method, and an observation method.

[0002] Light used for applications such as processing, measurement, and observation by light irradiation is required to have a time waveform suitable for the application. For example, in some cases, it is required to be an optical pulse train having a plurality of peaks temporally separated from each other. Light having a desired time waveform according to the application can be generated based on the optical pulses output from a pulsed laser light source.

[0003] For example, the accuracy and efficiency of processing a processing object by light irradiation depend on the time waveform of the light irradiated onto the processing object. In order to perform the processing of the processing object with high precision and high efficiency, it is important to irradiate the processing object with light having a desired time waveform. Therefore, it is important to measure the time waveform of the light generated based on the input optical pulse and to control the light irradiated onto the processing object so as to have a desired time waveform based on the measurement result. The time waveform of light can be measured using a cross-correlator or an autocorrelator.

[0004] The cross-correlator inputs light (target light) to be measured for the time waveform and also inputs a reference single optical pulse, and measures the shape of the cross-correlation between the time waveform of the target light and the time waveform of the reference single optical pulse. The time waveform of the target light can be obtained based on this cross-correlation shape.

[0005] The autocorrelator measures the shape of the autocorrelation of the time waveform of the target light. The time waveform of the target light can be obtained based on this autocorrelation shape (see Non-Patent Document 1).

[0006] Hikari Kogyo Co., Ltd., "Autocorrelation Method - Autocorrelator", [online], [Retrieved November 15, 2024], Internet <URL: https: / / www.symphotony.com / products / ultrashort / ultrashortmenu / autocorrelator / >

[0007] When measuring the time waveform of a target light using a cross-correlator, the time waveform of the target light can be estimated with relatively high accuracy. However, since the target light and the reference single optical pulse are input to the cross-correlator separately, the optical system leading up to the input of each of the target light and the reference single optical pulse must be adjusted each time a measurement is taken, and this adjustment is not easy.

[0008] On the other hand, when measuring the time waveform of target light using an autocorrelation analyzer, only the target light needs to be input to the autocorrelation analyzer, making the adjustment of the optical system until the target light is input to the autocorrelation analyzer relatively easy. Autocorrelation analyzers are easier to use than cross-correlation analyzers.

[0009] However, when the time waveform of the target light is complex, it is difficult to accurately determine the time waveform of the target light based on the autocorrelation shape. For example, when the target light is a light pulse train with two peaks spaced apart in time, it is difficult to estimate the difference in pulse shape or magnitude between these two peaks from the autocorrelation shape.

[0010] The embodiment aims to provide an apparatus and method that can easily and accurately measure the time waveform of target light.

[0011] The embodiment is an optical waveform measuring device. The optical waveform measuring device is a device for measuring the time waveform of a target light, and comprises: (1) a waveform generation unit that generates and outputs a target light and a reference single optical pulse based on an optical pulse output from a light source; (2) a measurement unit that inputs the target light and the reference single optical pulse at a time interval longer than the time width of the target light and the time width of the reference single optical pulse, and measures the shape of the autocorrelation of the time waveform of the light including the target light and the reference single optical pulse; and (3) a calculation unit that determines the time waveform of the target light based on the portion of the shape of the autocorrelation measured by the measurement unit that represents the cross-correlation between the time waveform of the target light and the time waveform of the reference single optical pulse.

[0012] The embodiment is a light irradiation device. The light irradiation device comprises a light waveform measuring device with the above configuration, a control unit that controls a waveform generation unit so that the time waveform of the target light determined by the calculation unit becomes a desired time waveform, and a light irradiation unit that irradiates an object with the target light output from the waveform generation unit.

[0013] The embodiment is a laser processing apparatus. The laser processing apparatus is equipped with a light irradiation device with the above configuration, and the light source is a laser light source.

[0014] The embodiment is an observation device. The observation device comprises a light irradiation device with the above configuration and a light detection unit that detects light from an object due to light irradiation.

[0015] The embodiment is a method for measuring optical waveforms. The optical waveform measurement method is a method for measuring the time waveform of a target light, comprising: (1) a waveform generation step of generating and outputting a target light and a reference single optical pulse based on an optical pulse output from a light source; (2) a measurement step of measuring the shape of the autocorrelation of the time waveform of the light including the target light and the reference single optical pulse; (3) a calculation step of determining the time waveform of the target light based on the portion of the shape of the autocorrelation measured in the measurement step that represents the cross-correlation between the time waveform of the target light and the time waveform of the reference single optical pulse; and (4) the target light and the reference single optical pulse are separated from each other by a time interval longer than the time width of the target light and the time width of the reference single optical pulse.

[0016] The embodiment is a light irradiation method. The light irradiation method is a method of irradiating an object with target light, and comprises: (1) a waveform generation step of generating and outputting target light and a reference single light pulse based on a light pulse output from a light source; (2) a measurement step of measuring the shape of the autocorrelation of the time waveform of the light including the target light and the reference single light pulse; (3) a calculation step of determining the time waveform of the target light based on the portion of the shape of the autocorrelation measured in the measurement step that represents the cross-correlation between the time waveform of the target light and the time waveform of the reference single light pulse; (4) a light control step of controlling the time waveform of the target light generated by the waveform generation step so that the time waveform of the target light determined in the calculation step becomes a desired time waveform; and (5) an irradiation step of irradiating the object with the target light controlled in the light control step and generated in the waveform generation step, wherein (6) the target light and the reference single light pulse are separated from each other by a time interval longer than the time width of the target light and the time width of the reference single light pulse.

[0017] The embodiment is a laser processing method. The laser processing method is a method for processing an object with target light, and comprises: (1) a waveform generation step of generating and outputting target light and a reference single optical pulse based on a laser light pulse output from a light source; (2) a measurement step of measuring the shape of the autocorrelation of the time waveform of light including the target light and the reference single optical pulse; (3) a calculation step of determining the time waveform of the target light based on the portion of the shape of the autocorrelation measured in the measurement step that represents the cross-correlation between the time waveform of the target light and the time waveform of the reference single optical pulse; (4) an optical control step of controlling the time waveform of the target light generated by the waveform generation step so that the time waveform of the target light determined in the calculation step becomes a desired time waveform; and (5) a processing step of focusing the target light controlled in the optical control step and generated in the waveform generation step onto or inside the object to process the object, and (6) the target light and the reference single optical pulse are separated from each other by a time interval longer than the time width of the target light and the time width of the reference single optical pulse.

[0018] The embodiment is an observation method. The observation method is a method for observing an object, and comprises: (1) a waveform generation step of generating and outputting a target light and a reference single light pulse based on a light pulse output from a light source; (2) a measurement step of measuring the shape of the autocorrelation of the time waveform of light including the target light and the reference single light pulse; (3) a calculation step of determining the time waveform of the target light based on the portion of the shape of the autocorrelation measured in the measurement step that represents the cross-correlation between the time waveform of the target light and the time waveform of the reference single light pulse; (4) a light control step of controlling the time waveform of the target light generated by the waveform generation step so that the time waveform of the target light determined in the calculation step becomes a desired time waveform; (5) a light irradiation step of focusing the target light controlled in the light control step and generated in the waveform generation step onto or inside the object; and (6) a light detection step of detecting the light focused in the light irradiation step and generated on the object, wherein (7) the target light and the reference single light pulse are separated from each other by a time interval longer than the time width of the target light and the time width of the reference single light pulse.

[0019] According to the embodiment of the optical waveform measuring device, optical irradiation device, laser processing device, observation device, optical waveform measuring method, optical irradiation method, laser processing method, and observation method, the time waveform of the target light can be measured simply and accurately.

[0020] Figure 1 is a diagram showing the configuration of the optical waveform measuring device 1. Figure 2 is a diagram illustrating the target optical light Po and reference single optical pulse Pr input to the measurement unit 30. Figure 3 is a diagram showing the configuration of the measurement unit 30. Figure 4 is a diagram illustrating the autocorrelation acquired by the measurement unit 30. Figure 5 is a diagram showing the configuration of the waveform generation unit 20A. Figure 6 is a diagram showing the configuration of the waveform generation unit 20B. Figure 7 is a diagram showing the configuration of the waveform generation unit 20C. Figure 8 is a diagram showing the configuration of the waveform generation unit 20D. Figure 9 is a diagram showing a part of the autocorrelation shape acquired by the measurement unit 30 in an experiment conducted using the configuration of the waveform generation unit 20D (Figure 8). Figure 10 is a diagram showing a part of the autocorrelation shape acquired by the measurement unit 30 in an experiment conducted using the configuration of the waveform generation unit 20D (Figure 8). Figure 11 is a diagram showing a part of the autocorrelation shape acquired by the measurement unit 30 in an experiment conducted using the configuration of the waveform generation unit 20D (Figure 8). Figure 12 is a flowchart showing an example of an optical waveform measurement method using the optical waveform measuring device 1. Figure 13 is a diagram showing the configuration of the optical irradiation device 2. Figure 14 is a flowchart showing an example of a light irradiation method using the light irradiation device 2. Figure 15 is a flowchart showing an example of a laser processing method using a laser processing device. Figure 16 is a flowchart showing an example of an observation method using a microscope device.

[0021] Embodiments of the optical waveform measuring device, optical irradiation device, laser processing device, observation device, optical waveform measuring method, optical irradiation method, laser processing method, and observation method will be described in detail below with reference to the attached drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant descriptions are omitted. This disclosure is not limited to these examples, but is indicated by the claims, and all modifications within the meaning and scope equivalent to the claims are intended.

[0022] Figure 1 shows the configuration of the optical waveform measuring device 1. The optical waveform measuring device 1 comprises a light source 10, a waveform generation unit 20, a measurement unit 30, and a calculation unit 40. The light source 10 repeatedly outputs optical pulses at a constant repetition frequency. The light source 10 is preferably a pulsed laser light source.

[0023] The waveform generation unit 20 is optically connected to the light source 10 and receives light pulses output from the light source 10 as input. Based on the input light pulses, the waveform generation unit 20 generates and outputs the light (target light) Po that is the subject of time waveform measurement, and also generates and outputs a reference single light pulse Pr.

[0024] The target light Po is generated to have a time waveform appropriate to the application. The reference single light pulse Pr may have the same time waveform as the light pulse output from the light source 10. Preferably, the reference single light pulse Pr has a time waveform with a narrower time width than the light pulse output from the light source 10.

[0025] The waveform generation unit 20 can be configured to include a dispersion element that outputs each wavelength component of the light pulse output from the light source 10 in a direction corresponding to the wavelength, and a spatial light modulator that inputs the light of each wavelength component output from the dispersion element and spatially modulates it. The dispersion element is, for example, a diffraction grating or a prism.

[0026] The waveform generation unit 20 may generate both the target light Po and the reference single light pulse Pr by modulating the light pulse based on the modulation pattern presented to the spatial light modulator. Alternatively, the waveform generation unit 20 may use a spatial light modulator that selectively modulates linearly polarized light of a first direction, and generate the target light Po by modulating the linearly polarized component of the light pulse in the first direction based on the modulation pattern presented to the spatial light modulator, while leaving the linearly polarized component of the light pulse in the second direction unmodulated as the reference single light pulse Pr. Specific configuration examples of the waveform generation unit 20 will be described later.

[0027] The measurement unit 30 is optically connected to the waveform generation unit 20 and inputs the target light Po and the reference single light pulse Pr output from the waveform generation unit 20 to a common input terminal. When inputting to this input terminal, the target light Po and the reference single light pulse Pr are input with a time interval ΔT that is longer than either the time width To of the target light Po or the time width Tr of the reference single light pulse Pr (Figure 2).

[0028] The above time interval ΔT is set based on the difference in optical path lengths between the target light Po and the reference single optical pulse Pr. The temporal order of the target light Po and the reference single optical pulse Pr at the time of input is arbitrary. The measurement unit 30 has the configuration of an autocorrelation analyzer and measures the shape of the autocorrelation of the time waveform of the light including the target light Po and the reference single optical pulse Pr.

[0029] The calculation unit 40 is electrically connected to the measurement unit 30 and receives autocorrelation data measured by the measurement unit 30. The calculation unit 40 determines the time waveform of the target light Po based on the portion of this autocorrelation shape that represents the cross-correlation between the time waveform of the target light Po and the time waveform of the reference single light pulse Pr.

[0030] The waveform generation unit 20 can control the generation of the target light Po so that the time waveform of the obtained target light Po becomes the desired time waveform. Furthermore, by using the target light Po with the desired time waveform, processing and measurement can be performed with higher precision and efficiency.

[0031] The optical waveform measurement method comprises a waveform generation step, a measurement step, and a calculation step. In the waveform generation step, the waveform generation unit 20 generates and outputs a target optical pulse Po and a reference single optical pulse Pr based on the optical pulse output from the light source 10.

[0032] In the measurement step, the measurement unit 30 receives the target light Po and the reference single light pulse Pr at a time interval longer than the time width of the target light Po and the time width of the reference single light pulse Pr, and measures the shape of the autocorrelation of the time waveforms of the light including the target light Po and the reference single light pulse Pr. In the calculation step, the time waveform of the target light Po is determined based on the portion of the autocorrelation shape measured in the measurement step that represents the cross-correlation between the time waveform of the target light Po and the time waveform of the reference single light pulse Pr.

[0033] Figure 3 shows the configuration of the measurement unit 30. The measurement unit 30 includes a beam splitter 31, mirrors 32a to 32f, a stage 33, a nonlinear optical element 34, and a photodetector 35.

[0034] The beam splitter 31 receives light including the target light Po and the reference single light pulse Pr output from the waveform generation unit 20, splits it into two, outputs one to mirror 32a and the other to mirror 32f. The splitting ratio of the beam splitter 31 may be 1:1. The light output from the beam splitter 31 to mirror 32a is sequentially reflected by mirrors 32a to 32e and input to the nonlinear optical element 34. The light output from the beam splitter 31 to mirror 32f is reflected by mirror 32f and input to the nonlinear optical element 34.

[0035] Mirrors 32c and 32d are mounted on the stage 33. The stage 33 is movable in the direction of the double arrows in the figure. Moving the stage 33 sets the difference in optical path length between the optical path from the beam splitter 31 through mirrors 32a to 32e to the nonlinear optical element 34 and the optical path from the beam splitter 31 through mirror 32f to the nonlinear optical element 34. In other words, by moving the stage 33, the time difference τ of the timing at which each of the two beams output from the beam splitter 31 reaches the nonlinear optical element 34 can be set to any value.

[0036] Two beams of light are incident on the nonlinear optical element 34 from different directions. This generates a second harmonic in the nonlinear optical element 34. For example, the nonlinear optical element 34 is KTP (KTiOPO) ４ ) crystal, LBO (LiB ３ O ５ Crystals such as ) crystals and BBO (β-BaB2O4) crystals are used.

[0037] The photodetector 35 detects the intensity of the second harmonic output from the nonlinear optical element 34 for each light pulse output from the light source 10. The intensity of this second harmonic corresponds to the magnitude of the correlation between the time waveforms of the two light beams incident on the nonlinear optical element 34, and corresponds to the magnitude of the autocorrelation of the time waveforms of the light including the target light Po and the reference single light pulse Pr.

[0038] When the time difference τ between the two lights incident on the nonlinear optical element 34 is set to each value by the movement of the stage 33, the intensity of the second harmonic wave output from the nonlinear optical element 34 is detected by the photodetector 35. The relationship between the time difference τ and the second harmonic wave intensity represents the shape of the autocorrelation of the time waveform of the light including the target light Po and the reference single light pulse Pr.

[0039] FIG. 4 is a diagram for explaining the autocorrelation acquired by the measurement unit 30. The autocorrelation G(τ) of a certain time waveform I(t) is represented by the following equation (1). Assume that the time waveform I(t) is represented by the sum of the time waveform Io(t) of the target light Po and the time waveform Ir(t) of the reference single light pulse Pr (the following equation (2)). At this time, the autocorrelation G(τ) is represented by the following equation (3). t is a variable representing time. τ is the time difference set by the stage 33.

[0040] The first term on the right side of this equation (3) represents the autocorrelation of the time waveform Io(t) of the target light Po. The second term represents the autocorrelation of the time waveform Ir(t) of the reference single light pulse Pr. Also, the third term and the fourth term represent the cross-correlation between the time waveform Io(t) of the target light Po and the time waveform Ir(t) of the reference single light pulse Pr.

[0041] The autocorrelation of the time waveform Io(t) of the target light Po in the first term and the autocorrelation of the time waveform Ir(t) of the reference single light pulse Pr in the second term overlap and distribute in a range including the time difference τ = 0 (range b in FIG. 4).

[0042] In contrast, the cross-correlation of the third term and the fourth term (the cross-correlation between the time waveform Io(t) of the target light Po and the time waveform Ir(t) of the reference single light pulse Pr) distributes in a range away from the time difference τ = 0 (ranges a and c in FIG. 4). Either one of the third term and the fourth term distributes in range a in FIG. 4, and the other distributes in range c in FIG. 4.

[0043] When input to the measurement unit 30, the target light Po and the reference single optical pulse Pr are input with a time interval ΔT longer than both the time width To of the target light Po and the time width Tr of the reference single optical pulse Pr, so that (FIG. 2), both of these ranges a and c are separated from the range b.

[0044] Therefore, from the shape of the autocorrelation acquired by the measurement unit 30, a portion (range a or range c in FIG. 4) representing the cross-correlation between the time waveform Io(t) of the target light Po and the time waveform Ir(t) of the reference single optical pulse Pr can be extracted. And based on the shape of the portion representing this cross-correlation, the time waveform Io(t) of the target light Po can be obtained.

[0045] Since the measurement unit 30 of the optical waveform measurement device 1 has the configuration of an autocorrelator, the adjustment of the optical system is easy and the use is convenient. Also, from the shape of the autocorrelation acquired by the measurement unit 30, a portion representing the cross-correlation between the time waveform Io(t) of the target light Po and the time waveform Ir(t) of the reference single optical pulse Pr is extracted, and based on the shape of the extracted portion representing this cross-correlation, the time waveform Io(t) of the target light Po can be obtained, so that the time waveform Io(t) of the target light Po can be accurately estimated.

[0046] From this, further, it becomes easy to generate the target light Po having the desired time waveform Io(t) by the waveform generation unit 20. Also, by using this target light Po, high-precision and high-efficiency processing and measurement can be performed.

[0047] Next, a specific configuration example of the waveform generation unit 20 will be described using FIGS. 5 to 8.

[0048] FIG. 5 is a diagram showing the configuration of the waveform generation unit 20A. The waveform generation unit 20A includes a diffraction grating 51, lenses 52 and 53, a spatial light modulator 54, a mirror 55, and a mirror 61.

[0049] The diffraction grating 51, acting as a dispersion element, receives the light pulse output from the light source 10 and diffracts the light pulse at a diffraction angle corresponding to its wavelength, thereby spatially separating the light pulse for each wavelength and outputting light of each wavelength in different directions. Lenses 52 and 53 receive the light of each wavelength that has been diffracted by the diffraction grating 51 and output in different directions, collimate it, and output the collimated light to the spatial light modulator 54.

[0050] The spatial light modulator 54 has a modulation plane that can modulate the phase of light at each pixel position. The spatial light modulator 54 inputs the light output after collimation by lenses 52 and 53 to the modulation plane, modulates the phase of the light at the modulation plane according to the position (i.e., according to the wavelength of the light), and outputs the modulated light. The spatial light modulator 54 may also be capable of amplitude modulation in addition to phase modulation of light at each pixel position. The modulation pattern at the modulation plane is presented by an external electrical signal.

[0051] The spatial light modulator 54 can adjust the time waveform of light by performing phase modulation according to the wavelength. Furthermore, the spatial light modulator 54 can adjust the spectral shape of light by performing amplitude modulation according to the wavelength.

[0052] Lenses 53 and 52 focus the light of each wavelength, which has been spatially modulated and output by the spatial light modulator 54, onto the diffraction grating 51. The diffraction grating 51 diffracts the light of each wavelength that has arrived from lenses 53 and 52 and outputs it as target light Po on the same optical path.

[0053] A portion of the light pulse output from the light source 10 passes through the diffraction grating 51 as zero-order light. The zero-order light that has passed through the diffraction grating 51 is reflected by the mirror 55 and passes through the diffraction grating 51 again. The diffraction grating 51 outputs this transmitted zero-order light as a reference single light pulse Pr.

[0054] The mirror 61 reflects the target light Po and the reference single light pulse Pr output from the diffraction grating 51 and outputs them to the measurement unit 30.

[0055] The waveform generation unit 20A may also include an optical stopper 59 that can be positioned in the optical path between the diffraction grating 51 and the mirror 55. The optical stopper 59 is positioned outside the optical path between the diffraction grating 51 and the mirror 55 during optical waveform measurement, while it is positioned in the optical path between the diffraction grating 51 and the mirror 55 during light irradiation or optical processing. This prevents the reference single optical pulse Pr from irradiating the target object S during light irradiation or optical processing.

[0056] Figure 6 shows the configuration of the waveform generation unit 20B. The waveform generation unit 20B includes a diffraction grating 51, lenses 52 and 53, a spatial light modulator 54, a half mirror 56, and a mirror 57.

[0057] The half-mirror 56 is a branching unit that receives the light pulse output from the light source 10 and splits it into a first branched light pulse and a second branched light pulse. The first branched light pulse is output to the diffraction grating 51, and the second branched light pulse is output to the mirror 57. The first branched light pulse output from the half-mirror 56 to the diffraction grating 51 is converted into a target light Po by the diffraction grating 51, lenses 52 and 53, and spatial light modulator 54 in the same manner as the waveform generation unit 20A (Figure 5), and returns to the half-mirror 56. The second branched light pulse output from the half-mirror 56 to the mirror 57 is reflected by the mirror 57 and then returns to the half-mirror 56 as a reference single light pulse Pr.

[0058] The half-mirror 56 receives the target light Po that has arrived from the diffraction grating 51 and the reference single light pulse Pr that has arrived from the mirror 57, combines both lights, and outputs the combined light to the measurement unit 30.

[0059] The waveform generation unit 20B may also include an optical stopper 59 that can be positioned in the optical path between the half mirror 56 and the mirror 57. The optical stopper 59 is positioned outside the optical path between the half mirror 56 and the mirror 57 during optical waveform measurement, while it is positioned in the optical path between the half mirror 56 and the mirror 57 during light irradiation or optical processing. This prevents the reference single optical pulse Pr from irradiating the object S during light irradiation or optical processing.

[0060] Figure 7 shows the configuration of the waveform generation unit 20C. The waveform generation unit 20C includes a diffraction grating 51, lenses 52, 53, a spatial light modulator 54, a mirror 57, a polarizing beam splitter 58, a mirror 61, half-wave plates 62, 63, and a polarizer 64.

[0061] The half-wave plate 62 receives the light pulse output from the light source 10, converts it into a light pulse having both p-polarized and s-polarized components, and outputs it. The polarization beam splitter 58 is a splitter that receives the light pulse output from the half-wave plate 62 and splits it into a p-polarized component and an s-polarized component. It outputs the p-polarized light pulse (first split light pulse) to the diffraction grating 51 and the s-polarized light pulse (second split light pulse) to the mirror 57.

[0062] The p-polarized light pulse output from the polarizing beam splitter 58 to the diffraction grating 51 is converted into the target light Po by the diffraction grating 51, lenses 52 and 53, and spatial light modulator 54 in the same manner as in the waveform generation unit 20A (Figure 5), and returns to the polarizing beam splitter 58. The s-polarized light pulse output from the polarizing beam splitter 58 to the mirror 57 is reflected by the mirror 57 and then returns to the polarizing beam splitter 58 as a reference single light pulse Pr.

[0063] The polarization beam splitter 58 receives p-polarized target light Po from the diffraction grating 51 and s-polarized reference single light pulse Pr from the mirror 57, combines both lights, and outputs the combined light to the mirror 61.

[0064] The mirror 61 reflects the p-polarized target light Po and the s-polarized reference single light pulse Pr output from the polarizing beam splitter 58 onto the half-wave plate 63. The half-wave plate 63 rotates the polarization direction of both the target light Po and the reference single light pulse Pr by 45 degrees and outputs them to the polarizer 64. The polarizer 64 selectively transmits one linearly polarized component of the target light Po and the reference single light pulse Pr output from the half-wave plate 63 and outputs it to the measurement unit 30.

[0065] The waveform generation unit 20C may also include an optical stopper 59 that can be positioned in the optical path between the polarizing beam splitter 58 and the mirror 57. The optical stopper 59 is positioned outside the optical path between the polarizing beam splitter 58 and the mirror 57 during optical waveform measurement, while being positioned in the optical path between the polarizing beam splitter 58 and the mirror 57 during light irradiation or optical processing. This prevents the reference single optical pulse Pr from irradiating the target object S during light irradiation or optical processing.

[0066] If the autocorrelation analyzer of the measurement unit 30 is polarization-dependent, it is preferable to input a linearly polarized component in one direction from the target light Po and the reference single light pulse Pr to the measurement unit 30 in this manner. Furthermore, in this configuration, the intensity ratio between the target light Po and the reference single light pulse Pr can be adjusted using the half-wave plates 62 and 63, so that the light intensity conditions can be optimized when measuring the autocorrelation shape.

[0067] Figure 8 shows the configuration of the waveform generation unit 20D. The waveform generation unit 20D includes a half-wave plate 71, a polarizing beam splitter 72, a half-wave plate 73, a diffraction grating 74, a lens 75, a spatial light modulator 76, a mirror 77, a half-wave plate 78, a mirror 79, a polarizing beam splitter 81, a half-wave plate 82, and a polarizing beam splitter 83.

[0068] The half-wave plate 71 receives the light pulse output from the light source 10, converts it into a light pulse having both p-polarized and s-polarized components, and outputs it. The polarization beam splitter 72 is a branching unit that receives the light pulse output from the half-wave plate 71 and splits it into a p-polarized component and an s-polarized component, outputting the p-polarized light pulse to the half-wave plate 73 and the s-polarized light pulse to the half-wave plate 78.

[0069] The half-wave plate 73 converts the p-polarized light pulses arriving from the polarizing beam splitter 72 into s-polarized light pulses, and outputs these converted s-polarized light pulses to the diffraction grating 74. The s-polarized light pulses output from the half-wave plate 73 to the diffraction grating 74 are converted into target light Po by the diffraction grating 74, lens 75, and spatial light modulator 76, in the same manner as the diffraction grating 51, lenses 52, 53, and spatial light modulator 54 of the waveform generation unit 20A (Figure 5). The mirror 77 reflects this target light Po to the polarizing beam splitter 81.

[0070] The half-wave plate 78 converts the s-polarized light pulses arriving from the polarizing beam splitter 72 into p-polarized light, and outputs these converted p-polarized light pulses to the mirror 79. The mirror 79 reflects the p-polarized light pulses output from the half-wave plate 78 as a reference single light pulse Pr to the polarizing beam splitter 81.

[0071] The polarization beam splitter 81 receives the s-polarized target light Po arriving from the mirror 77 and the p-polarized reference single light pulse Pr arriving from the mirror 79, combines the two lights, and outputs them to the half-wave plate 82. The half-wave plate 82 receives the target light Po and the reference single light pulse Pr output from the polarization beam splitter 81, rotates the polarization direction of both lights by 45 degrees, and outputs them to the polarization beam splitter 83. The polarization beam splitter 83 selectively transmits the p-polarized component of the target light Po and the reference single light pulse Pr output from the half-wave plate 82 and outputs it to the measurement unit 30.

[0072] The waveform generation unit 20D may also include an optical stopper 59 that can be positioned in the optical path between the polarizing beam splitter 72 and the polarizing beam splitter 81. The optical stopper 59 is positioned outside the optical path between the polarizing beam splitter 72 and the polarizing beam splitter 81 during optical waveform measurement, while being positioned in the optical path between the polarizing beam splitter 72 and the polarizing beam splitter 81 during light irradiation or optical processing. This prevents the reference single optical pulse Pr from irradiating the object S during light irradiation or optical processing.

[0073] In this configuration as well, if the autocorrelation analyzer of the measurement unit 30 is polarization-dependent, a linearly polarized component in one direction of the target light Po and the reference single light pulse Pr can be input to the measurement unit 30. Furthermore, since the intensity ratio between the target light Po and the reference single light pulse Pr can be adjusted using the half-wave plates 71 and 82, the light intensity conditions can be optimized when measuring the autocorrelation shape.

[0074] Figures 9 to 11 show the autocorrelation shapes obtained by the measurement unit 30 in experiments conducted using the configuration of the waveform generation unit 20D (Figure 8). In all cases, the time interval ΔT between the target light Po and the reference single light pulse Pr was set to approximately 100 ps.

[0075] The autocorrelation shape shown in Figure 9 was obtained for the target light Po (2 peaks, peak interval 0.5 ps) generated by phase modulation only by the spatial light modulator 76 of the waveform generation unit 20D. The autocorrelation shape shown in Figure 10 was obtained for the target light Po (2 peaks, peak interval 2 ps) generated by phase modulation only by the spatial light modulator 76 of the waveform generation unit 20D. The autocorrelation shape shown in Figure 11 was obtained for the target light Po (5 peaks, peak interval 0.5 ps) generated by phase modulation and intensity modulation by the spatial light modulator 76 of the waveform generation unit 20D.

[0076] In all of these autocorrelation shapes, it can be observed that the cross-correlation between the time waveform of the target light Po and the time waveform of the reference single light pulse Pr is distributed within the range including the time difference τ = 100 ps. Based on this cross-correlation shape, the time waveform of the target light Po can be accurately determined.

[0077] Figure 12 is a flowchart showing an example of an optical waveform measurement method using the optical waveform measuring device 1. In the waveform generation step S11, the target light Po and a reference single light pulse Pr are generated and output based on the light pulse output from the light source 10. In the measurement step S12, the shape of the autocorrelation of the time waveform of the light including the target light Po and the reference single light pulse Pr is measured.

[0078] In calculation step S13, the time waveform of the target light Po is determined based on the portion of the autocorrelation shape measured in measurement step S12 that represents the cross-correlation between the time waveform of the target light Po and the time waveform of the reference single light pulse Pr. Note that the target light Po and the reference single light pulse Pr generated in waveform generation step S11 are separated from each other by a time interval longer than the time width of either the target light Po or the time width of the reference single light pulse Pr.

[0079] Figure 13 shows the configuration of the light irradiation device 2. In addition to the configuration of the light waveform measuring device 1 shown in Figure 1, the light irradiation device 2 includes a control unit 91, a mirror 92, and a light irradiation unit 93. The light irradiation device 2 controls the generation of the target light Po by the waveform generation unit 20 so that the time waveform of the target light Po determined by the calculation unit 40 becomes the desired time waveform, and irradiates the target object S with the target light Po via the light irradiation unit 93.

[0080] The control unit 91 controls the generation of the target light Po by the waveform generation unit 20 so that the time waveform of the target light Po determined by the calculation unit 40 becomes the desired time waveform. For example, if the waveform generation unit 20 is equipped with a spatial light modulator 76, the control unit 91 presents a modulation pattern that results in the desired time waveform to the spatial light modulator 76. As a result, the waveform generation unit 20 generates the target light Po having the desired time waveform. At this time, by positioning the optical stopper 59 in the waveform generation unit 20 at a predetermined position on the optical path, it is possible to prevent the reference single optical pulse Pr from being emitted from the waveform generation unit 20.

[0081] Furthermore, during light irradiation, a mirror 92 is inserted in the optical path between the waveform generation unit 20 and the measurement unit 30. This allows the target light Po emitted from the waveform generation unit 20 to be guided to the light irradiation unit 93. The light irradiation unit 93 is, for example, a focusing optical element such as an objective lens or a focusing lens, which focuses the target light Po onto or inside the object S.

[0082] The light irradiation device 2 may not merely irradiate light, but may also be a laser processing device that processes the target object S. The laser processing device processes the target object S by focusing and irradiating the surface or interior of the target object S with target light Po, which has a desired time waveform, using the light irradiation unit 93. In this case, it is preferable that the light source 10 is a laser light source.

[0083] The light irradiation device 2 may be used together with the light detection unit 94. An observation device comprising the light irradiation device 2 and the light detection unit 94 can observe the object S by focusing and irradiating the surface or interior of the object S with target light Po, which has a desired time waveform, using the light irradiation unit 93, and detecting the light from the object S due to the light irradiation with the light detection unit 94.

[0084] Figure 14 is a flowchart showing an example of a light irradiation method using the light irradiation device 2. The waveform generation step S11, measurement step S12, and calculation step S13 are the same as those described in Figure 12.

[0085] In the determination step S14, it is determined whether the time waveform of the target light Po obtained in the calculation step S13 is the desired time waveform. If it is determined in the determination step S14 that the time waveform of the target light Po is not the desired time waveform, in the light control step S15, the time waveform of the target light Po generated in the waveform generation step S11 is controlled so that the time waveform of the target light Po obtained in the calculation step S13 becomes the desired time waveform. These steps are repeated.

[0086] If it is determined in the determination step S14 that the time waveform of the target light Po is the desired time waveform, the target light Po is irradiated onto the target object S in the light irradiation step S16. At this time, the light stopper 59 may be placed on a predetermined optical path to block the reference single light pulse Pr. The target light Po and the reference single light pulse Pr generated in the waveform generation step S11 are separated from each other by a time interval that is longer than the time width of either the target light Po or the time width of the reference single light pulse Pr.

[0087] Thus, with the light irradiation device 2 and the light irradiation method, it is possible to irradiate the target object S with target light Po having a desired time waveform.

[0088] For example, if the light irradiation device 2 is part of a laser processing device, it is possible to focus the target light Po, which has an optimal time waveform for processing the target object S such as a metal plate or semiconductor wafer, onto or inside the target object S, thereby improving processing accuracy. Also, if the light irradiation device 2 is part of a microscope device, it is possible to focus the target light Po, which has an optimal time waveform for observing the target object S such as a biological sample such as cells, onto or inside the target object S, thereby improving observation accuracy.

[0089] Figure 15 is a flowchart showing an example of a laser processing method using a laser processing apparatus. The waveform generation step S11, measurement step S12, calculation step S13, determination step S14, and optical control step S15 are the same as those described in Figure 14. However, it is preferable that the optical pulse output from the light source 10 is laser light.

[0090] If it is determined in the determination step S14 that the time waveform of the target light Po is a desired time waveform, in the processing step S17, the target light Po is focused onto or inside the target object S to process the target object S. At this time, the light stopper 59 may be placed on a predetermined optical path to block the reference single light pulse Pr. The target light Po and the reference single light pulse Pr generated in the waveform generation step S11 are separated from each other by a time interval that is longer than the time width of either the target light Po or the time width of the reference single light pulse Pr.

[0091] Figure 16 is a flowchart showing an example of an observation method using a microscope (observation device). The waveform generation step S11, measurement step S12, calculation step S13, determination step S14, light control step S15, and light irradiation step S16 are the same as those described in Figure 14.

[0092] In the light detection step S18, light from the object S generated by the light irradiation step S16 (e.g., fluorescence, reflected light, transmitted light, scattered light, etc.) is detected by a photodetector (e.g., a point sensor, line sensor, or area sensor). The target light Po and the reference single light pulse Pr generated in the waveform generation step S11 are separated from each other by a time interval longer than the time width of either the target light Po or the time width of the reference single light pulse Pr.

[0093] The optical waveform measuring device, optical irradiation device, laser processing device, observation device, optical waveform measuring method, optical irradiation method, laser processing method, and observation method are not limited to the embodiments and configuration examples described above, and various modifications are possible.

[0094] The optical waveform measuring device according to the first embodiment described above is a device for measuring the time waveform of a target light, comprising: (1) a waveform generation unit that generates and outputs a target light and a reference single optical pulse based on an optical pulse output from a light source; (2) a measurement unit that inputs the target light and the reference single optical pulse at a time interval longer than the time width of the target light and the time width of the reference single optical pulse, and measures the shape of the autocorrelation of the time waveform of the light including the target light and the reference single optical pulse; and (3) a calculation unit that determines the time waveform of the target light based on the portion of the shape of the autocorrelation measured by the measurement unit that represents the cross-correlation between the time waveform of the target light and the time waveform of the reference single optical pulse.

[0095] In the optical waveform measuring device of the second embodiment, the waveform generation unit may be configured to include a dispersion element that outputs each wavelength component of an optical pulse output from a light source in a direction corresponding to the wavelength, and a spatial light modulator that receives the light of each wavelength component output from the dispersion element, spatially modulates it, and generates a target light and a reference single optical pulse.

[0096] In the optical waveform measuring device of the third embodiment, the waveform generation unit may be configured to include a dispersion element that outputs each wavelength component of an optical pulse output from a light source in a direction corresponding to the wavelength, and a spatial light modulator that receives the light of each wavelength component output from the dispersion element, inputs the linearly polarized component of the first direction, spatially modulates it to generate target light, and uses the linearly polarized component of the second direction as a reference single optical pulse without modulation.

[0097] In the optical waveform measuring device of the fourth embodiment, in the configuration of the first embodiment, the waveform generation unit includes a diffraction grating that outputs each wavelength component of an optical pulse output from a light source in a direction corresponding to the wavelength, and a spatial light modulator that receives the light of each wavelength component diffracted and output by the diffraction grating, spatially modulates it, and generates target light, and the zeroth-order light generated by the diffraction grating may be configured to be a reference single optical pulse.

[0098] In the fifth embodiment of the optical waveform measuring device, in the configuration of the first embodiment, the waveform generation unit comprises a branching unit that splits an optical pulse output from a light source into two and outputs a first branched optical pulse and a second branched optical pulse, a dispersion element that outputs each wavelength component of the first branched optical pulse in a direction corresponding to the wavelength, and a spatial optical modulator that receives the light of each wavelength component output from the dispersion element and spatially modulates it to generate target light, and the second branched optical pulse may be configured to be a reference single optical pulse.

[0099] In the sixth embodiment of the optical waveform measuring device, in any of the configurations of the first to fifth embodiments, the waveform generation unit may further include an optical stopper for blocking a reference single optical pulse.

[0100] The light irradiation device according to the above embodiment comprises a light waveform measuring device configured in any of the first to sixth embodiments, a control unit that controls a waveform generation unit so that the time waveform of the target light determined by the calculation unit becomes a desired time waveform, and a light irradiation unit that irradiates an object with the target light output from the waveform generation unit.

[0101] The laser processing apparatus according to the above embodiment includes a light irradiation device with the above configuration, and the light source is a laser light source.

[0102] The observation device according to the above embodiment comprises a light irradiation device with the above configuration and a light detection unit that detects light from an object due to light irradiation.

[0103] The first embodiment of the optical waveform measurement method according to the above embodiment is a method for measuring the time waveform of a target light, comprising: (1) a waveform generation step of generating and outputting a target light and a reference single optical pulse based on an optical pulse output from a light source; (2) a measurement step of measuring the shape of the autocorrelation of the time waveform of the light including the target light and the reference single optical pulse; and (3) a calculation step of determining the time waveform of the target light based on the portion of the shape of the autocorrelation measured in the measurement step that represents the cross-correlation between the time waveform of the target light and the time waveform of the reference single optical pulse, wherein (4) the target light and the reference single optical pulse are separated from each other by a time interval longer than the time width of the target light and the time width of the reference single optical pulse.

[0104] The optical waveform measurement method according to the above embodiment is a method for measuring the time waveform of a target light, and may be configured to include: (1) a waveform generation step in which a waveform generation unit generates and outputs a target light and a reference single optical pulse based on an optical pulse output from a light source; (2) a measurement step in which a measurement unit inputs the target light and the reference single optical pulse at a time interval longer than the time width of the target light and the time width of the reference single optical pulse, and measures the shape of the autocorrelation of the time waveform of the light including the target light and the reference single optical pulse; and (3) a calculation step in which the time waveform of the target light is determined based on the portion of the shape of the autocorrelation measured in the measurement step that represents the cross-correlation between the time waveform of the target light and the time waveform of the reference single optical pulse.

[0105] In the second embodiment of the optical waveform measurement method, in the configuration of the first embodiment, in the waveform generation step, each wavelength component of the optical pulse output from the light source is output in a direction corresponding to the wavelength by a dispersive element, and the light is spatially modulated by a spatial light modulator that receives the light of each wavelength component output from the dispersive element to generate the target light and a reference single optical pulse.

[0106] In the third embodiment of the optical waveform measurement method, in the configuration of the first embodiment, in the waveform generation step, each wavelength component of the optical pulse output from the light source is output in a direction corresponding to the wavelength by a dispersive element, and the linearly polarized component of the first direction of the light is input to a spatial light modulator that receives the light of each wavelength component output from the dispersive element, and is spatially modulated to generate the target light, while the linearly polarized component of the second direction is left unmodulated as a reference single optical pulse.

[0107] In the fourth embodiment of the optical waveform measurement method, in the configuration of the first embodiment, in the waveform generation step, each wavelength component of the optical pulse output from the light source is output in a direction corresponding to the wavelength by a diffraction grating, and the light of each wavelength component diffracted and output by the diffraction grating is input to a spatial light modulator, which then spatially modulates the light to generate the target light, and the zeroth-order light generated by the diffraction grating is used as the reference single optical pulse.

[0108] In the fifth embodiment of the optical waveform measurement method, in the configuration of the first embodiment, in the waveform generation step, the optical pulse output from the light source is split into two by a branching unit to output a first branched optical pulse and a second branched optical pulse, each wavelength component of the first branched optical pulse is output in a direction corresponding to the wavelength by a dispersive element, and the light of each wavelength component output from the dispersive element is spatially modulated by a spatial light modulator to generate target light, and the second branched optical pulse may be configured as a reference single optical pulse.

[0109] The light irradiation method according to the above embodiment is a method of irradiating an object with target light, comprising: (1) a waveform generation step of generating and outputting target light and a reference single light pulse based on a light pulse output from a light source; (2) a measurement step of measuring the shape of the autocorrelation of the time waveform of the light including the target light and the reference single light pulse; (3) a calculation step of determining the time waveform of the target light based on the portion of the shape of the autocorrelation measured in the measurement step that represents the cross-correlation between the time waveform of the target light and the time waveform of the reference single light pulse; (4) a light control step of controlling the time waveform of the target light generated by the waveform generation step so that the time waveform of the target light determined in the calculation step becomes a desired time waveform; and (5) an irradiation step of irradiating an object with the target light controlled in the light control step and generated in the waveform generation step, wherein (6) the target light and the reference single light pulse are separated from each other by a time interval longer than the time width of the target light and the time width of the reference single light pulse.

[0110] The laser processing method according to the above embodiment is a method for processing an object with target light, comprising: (1) a waveform generation step of generating and outputting target light and a reference single optical pulse based on a laser light pulse output from a light source; (2) a measurement step of measuring the shape of the autocorrelation of the time waveform of light including the target light and the reference single optical pulse; (3) a calculation step of determining the time waveform of the target light based on the portion of the shape of the autocorrelation measured in the measurement step that represents the cross-correlation between the time waveform of the target light and the time waveform of the reference single optical pulse; (4) an optical control step of controlling the time waveform of the target light generated by the waveform generation step so that the time waveform of the target light determined in the calculation step becomes a desired time waveform; and (5) a processing step of focusing the target light controlled in the optical control step and generated in the waveform generation step onto or inside the object to process the object, wherein (6) the target light and the reference single optical pulse are separated from each other by a time interval longer than the time width of the target light and the time width of the reference single optical pulse.

[0111] The observation method according to the above embodiment is a method for observing an object, comprising: (1) a waveform generation step of generating and outputting target light and a reference single light pulse based on light pulses output from a light source; (2) a measurement step of measuring the shape of the autocorrelation of the time waveform of light including the target light and the reference single light pulse; (3) a calculation step of determining the time waveform of the target light based on the portion of the shape of the autocorrelation measured in the measurement step that represents the cross-correlation between the time waveform of the target light and the time waveform of the reference single light pulse; (4) a light control step of controlling the time waveform of the target light generated by the waveform generation step so that the time waveform of the target light determined in the calculation step becomes a desired time waveform; (5) a light irradiation step of focusing the target light controlled in the light control step and generated in the waveform generation step onto or inside the object; and (6) a light detection step of detecting the light generated on the object by the light irradiation step, wherein (7) the target light and the reference single light pulse are separated from each other by a time interval longer than the time width of the target light and the time width of the reference single light pulse.

[0112] The embodiment can be used as an apparatus and method for easily and accurately measuring the time waveform of target light.

[0113] 1...Optical waveform measuring device, 2...Optical irradiation device (laser processing device, observation device), 10...Light source, 20, 20A-20D...Waveform generation unit, 30...Measurement unit, 31...Beam splitter, 32a-32f...Mirror, 33...Stage, 34...Nonlinear optical element, 35...Photodetector, 40...Calculation unit, 51...Diffraction grating, 52, 53...Lens, 54...Spatial light modulator, 55...Mirror, 56...Half mirror, 57...Mirror, 58...Polarizing beam splitter, 59... Light stopper, 61...Mirror, 62, 63...Half wave plate, 64...Polarizer, 71...Half wave plate, 72...Polarizing beam splitter, 73...Half wave plate, 74...Diffraction grating, 75...Lens, 76...Spatial light modulator, 77...Mirror, 78...Half wave plate, 79...Mirror, 81...Polarizing beam splitter, 82...Half wave plate, 83...Polarizing beam splitter, 91...Control unit, 92...Mirror, 93...Light irradiation unit, 94...Light detection unit, S...Target object.

Claims

1. An optical waveform measuring device comprising: a waveform generation unit that generates and outputs the target light and a reference single optical pulse based on an optical pulse output from a light source; a measurement unit that inputs the target light and the reference single optical pulse at a time interval longer than the time width of the target light and the time width of the reference single optical pulse, and measures the shape of the autocorrelation of the optical waveform including the target light and the reference single optical pulse; and a calculation unit that determines the time waveform of the target light based on the portion of the autocorrelation shape measured by the measurement unit that represents the cross-correlation between the time waveform of the target light and the time waveform of the reference single optical pulse.

2. The optical waveform measuring device according to claim 1, wherein the waveform generation unit comprises a dispersion element that outputs each wavelength component of an optical pulse output from the light source in a direction corresponding to the wavelength, and a spatial light modulator that receives the light of each wavelength component output from the dispersion element, spatially modulates it, and generates the target light and the reference single optical pulse.

3. The optical waveform measuring device according to claim 1, wherein the waveform generation unit comprises: a dispersion element that outputs each wavelength component of an optical pulse output from the light source in a direction corresponding to the wavelength; and a spatial light modulator that receives the light of each wavelength component output from the dispersion element, inputs the linearly polarized component of the first direction, spatially modulates it to generate the target light, and uses the linearly polarized component of the second direction unmodulated as the reference single optical pulse.

4. The optical waveform measuring device according to claim 1, wherein the waveform generation unit comprises a diffraction grating that outputs each wavelength component of an optical pulse output from the light source in a direction corresponding to the wavelength, and a spatial light modulator that receives the light of each wavelength component diffracted and output by the diffraction grating, spatially modulates it to generate the target light, and the zeroth-order light generated by the diffraction grating is used as the reference single optical pulse.

5. The optical waveform measuring device according to claim 1, wherein the waveform generation unit comprises: a branching unit that branches an optical pulse output from the light source into two and outputs a first branched optical pulse and a second branched optical pulse; a dispersion element that outputs each wavelength component of the first branched optical pulse in a direction corresponding to the wavelength; and a spatial optical modulator that receives the light of each wavelength component output from the dispersion element and spatially modulates it to generate the target light, and the second branched optical pulse is the reference single optical pulse.

6. The optical waveform measuring apparatus according to any one of claims 1 to 5, wherein the waveform generation unit further comprises an optical stopper for blocking the reference single optical pulse.

7. A light irradiation device comprising: an optical waveform measuring device according to any one of claims 1 to 6; a control unit that controls the waveform generation unit so that the time waveform of the target light determined by the calculation unit becomes a desired time waveform; and a light irradiation unit that irradiates an object with the target light output from the waveform generation unit.

8. A laser processing apparatus comprising the light irradiation device described in claim 7, wherein the light source is a laser light source.

9. An observation device comprising: a light irradiation device according to claim 7; and a light detection unit for detecting light from an object due to light irradiation.

10. A method for measuring the time waveform of a target light, comprising: a waveform generation step of generating and outputting the target light and a reference single light pulse based on light pulses output from a light source; a measurement step of measuring the shape of the autocorrelation of the time waveform of the light including the target light and the reference single light pulse; and a calculation step of determining the time waveform of the target light based on the portion of the shape of the autocorrelation measured in the measurement step that represents the cross-correlation between the time waveform of the target light and the time waveform of the reference single light pulse, wherein the target light and the reference single light pulse are separated from each other by a time interval longer than the time width of the target light and the time width of the reference single light pulse.

11. A method for irradiating an object with target light, comprising: a waveform generation step of generating and outputting target light and a reference single light pulse based on a light pulse output from a light source; a measurement step of measuring the shape of the autocorrelation of the time waveform of light including the target light and the reference single light pulse; a calculation step of determining the time waveform of the target light based on the portion of the shape of the autocorrelation measured in the measurement step that represents the cross-correlation between the time waveform of the target light and the time waveform of the reference single light pulse; a light control step of controlling the time waveform of the target light generated by the waveform generation step so that the time waveform of the target light determined in the calculation step becomes a desired time waveform; and an irradiation step of irradiating the object with the target light controlled in the light control step and generated in the waveform generation step, wherein the target light and the reference single light pulse are separated from each other by a time interval longer than the time width of the target light and the time width of the reference single light pulse.

12. A laser processing method for processing an object with target light, comprising: a waveform generation step of generating and outputting target light and a reference single optical pulse based on a laser light pulse output from a light source; a measurement step of measuring the shape of the autocorrelation of the time waveform of light including the target light and the reference single optical pulse; a calculation step of determining the time waveform of the target light based on the portion of the shape of the autocorrelation measured in the measurement step that represents the cross-correlation between the time waveform of the target light and the time waveform of the reference single optical pulse; an optical control step of controlling the time waveform of the target light generated by the waveform generation step so that the time waveform of the target light determined in the calculation step becomes a desired time waveform; and a processing step of focusing the target light, which is controlled in the optical control step and generated in the waveform generation step, onto or inside the object to process the object, wherein the target light and the reference single optical pulse are separated from each other by a time interval longer than the time width of the target light and the time width of the reference single optical pulse.

13. A method for observing an object, comprising: a waveform generation step of generating and outputting a target light and a reference single light pulse based on a light pulse output from a light source; a measurement step of measuring the shape of the autocorrelation of the time waveform of light including the target light and the reference single light pulse; a calculation step of determining the time waveform of the target light based on the portion of the shape of the autocorrelation measured in the measurement step that represents the cross-correlation between the time waveform of the target light and the time waveform of the reference single light pulse; a light control step of controlling the time waveform of the target light generated by the waveform generation step so that the time waveform of the target light determined in the calculation step becomes a desired time waveform; a light irradiation step of focusing the target light controlled in the light control step and generated in the waveform generation step onto or inside the object; and a light detection step of detecting the light focused in the light irradiation step and generated on the object, wherein the target light and the reference single light pulse are separated from each other by a time interval longer than the time width of the target light and the time width of the reference single light pulse.

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