CN-122008703-A - Femtosecond oscillator and femtosecond laser source for two-photon printing

CN122008703ACN 122008703 ACN122008703 ACN 122008703ACN-122008703-A

Abstract

The application provides a femtosecond oscillator and a femtosecond laser source for two-photon printing, which relate to the technical field of laser application, wherein the femtosecond oscillator can directly emit high-energy short-pulse femtosecond laser with a wave band of 700 nm-800 nm or a wave band of 500 nm-560 nm without a pulse width widening, multistage amplification and frequency doubling system, and the structural complexity of the femtosecond laser source for two-photon printing is greatly simplified.

Inventors

YANG HAOLIN
HE ZEWEI
CHEN WEILIN

Assignees

乾元国家实验室

Dates

Publication Date: 20260512
Application Date: 20260225

Claims (10)

1. The femtosecond oscillator is characterized by comprising a pump source system and a femtosecond oscillation module, wherein the femtosecond oscillation module comprises a linear mamyshov oscillator, a holmium-doped fluoride optical fiber and a tapering optical fiber, wherein the holmium-doped fluoride optical fiber and the tapering optical fiber are arranged between the linear mamyshov oscillators, the linear mamyshov oscillator is composed of a first reflective diffraction grating and a second reflective diffraction grating which are respectively arranged at a Littrow angle, a pump beam coupled in by the pump source system is incident on the holmium-doped fluoride optical fiber to generate laser gain, and the laser gain oscillates between the first reflective diffraction grating and the second reflective diffraction grating through the tapering optical fiber so that the laser beam after the broadening covers the reflection wavelengths of the first reflective diffraction grating and the second reflective diffraction grating.
2. The femtosecond oscillator according to claim 1, wherein the pump source system comprises a signal generator, a laser diode driver, and a visible light band laser diode, the signal generator outputting a periodic signal to the laser diode driver to drive the visible light band laser diode pulse output, or the signal generator outputting a direct current signal to the laser diode driver to drive the visible light band laser diode to output a continuous wave.
3. The femtosecond oscillator according to claim 2, wherein the visible light band laser diode is a blue laser diode.
4. The femtosecond oscillator according to claim 2, further comprising a pump optical coupling module disposed between a pump source system and the femtosecond oscillation module, wherein the pump optical coupling module comprises at least one convex lens, a dichroic mirror is further disposed in the femtosecond oscillation module, and the pump light beam is coupled into the holmium-doped fluoride optical fiber through the dichroic mirror after being collimated and focused by the pump optical coupling module.
5. The femtosecond oscillator according to any one of claims 1 to 4, wherein the femtosecond oscillation module further comprises an output coupling device including a first half wave plate and a polarization beam splitter, and a polarization transmission axis of the first half wave plate is adjusted to reflect a part of the laser beam out through the polarization beam splitter.
6. The femtosecond oscillator according to claim 1, wherein a reflection wavelength of the first reflective diffraction grating is 745nm and a reflection wavelength of the second reflective diffraction grating is 752nm; the length of the holmium-doped fluoride optical fiber is 1.5m, and the length of the tapered optical fiber is 0.5m.
7. A femtosecond laser source, comprising the femtosecond oscillator as set forth in any one of claims 1 to 6, and a pulse width compression system, wherein the laser beam emitted after the spectrum broadening of the femtosecond oscillator is emitted after the pulse width is compressed in the pulse width compression system.
8. The femtosecond laser source according to claim 7, wherein the pulse width compression system comprises a second half-wave plate, a Treacy type compressor and a roof prism reflector, wherein the light beam emitted after spectrum broadening of the femtosecond oscillator enters the Treacy type compressor to compress the pulse width of the laser after the polarization direction of the light beam is adjusted by the second half-wave plate, and the obtained light beam with compressed pulse width is emitted by the roof prism reflector.
9. The femtosecond laser source according to claim 8, wherein said Treacy type compressor includes a first transmission diffraction grating and a second transmission diffraction grating disposed in parallel opposite to each other, and a laser beam is emitted toward said roof prism mirror after compressing a pulse width in said Treacy type compressor.
10. The femtosecond laser source according to claim 9, further comprising a high-reflectivity plane mirror disposed on an optical path of a reflection direction of the roof prism reflector, wherein the compressed pulse width laser beam reflected by the roof prism reflector is reflected out through a turning optical path of the high-reflectivity plane mirror.

Description

Femtosecond oscillator and femtosecond laser source for two-photon printing Technical Field The application relates to the technical field of laser application, in particular to a femtosecond oscillator and a femtosecond laser source for two-photon printing. Background The basic principle of two-photon polymerization printing is derived from the two-photon absorption theory proposed by Maria Goeppert-Mayer in 1931, and the application of the two-photon technology is not really started until the 1997 japanese scientist s. Maruo realizes micron-sized three-dimensional structure printing in photoresist by femtosecond laser for the first time. The two-photon printing is based on nonlinear optical effect, when femto-second laser focuses on photosensitive resin, resin molecules absorb two near infrared photons at the same time, when the total energy absorbed exceeds a polymerization threshold, the resin can be crosslinked and solidified in a volume with extremely small laser focus, and the nonlinear effect is only activated in a high light intensity area, so that the processing resolution breaks through the optical diffraction limit and can reach below 100 nm. The wavelength of the femtosecond laser light source for the two-photon printing is generally located in the visible light and near infrared bands, wherein the laser light sources of 780 nm and 532 nm are low in scattering and absorptivity in photosensitive resin and can penetrate hundreds of microns in depth, so that the internal printing of a deep structure can be realized, and the application of the 700 nm-800 nm band and the 500 nm-560 nm visible light band in the two-photon printing is the most widely. At present, the laser sources of 700 nm-800 nm wave bands and 500 nm-560 nm visible light wave bands are mainly obtained through a nonlinear frequency doubling technology, the laser systems of the two wave bands are long in link, the whole structure is complex, and the laser sources generally comprise five parts, namely an infrared femtosecond laser seed source, a seed source pulse width stretcher, a one-stage or multi-stage amplifying system, a pulse width compressor and a frequency doubling system. Disclosure of Invention The application provides a femtosecond oscillator and a femtosecond laser source for two-photon printing, wherein the femtosecond oscillator can directly emit high-energy short-pulse femtosecond laser with a wave band of 700 nm-800 nm or a wave band of 500 nm-560 nm without a pulse width widening, multistage amplification and frequency doubling system, so that the structural complexity of the femtosecond laser source for two-photon printing is greatly simplified. In order to achieve the above purpose, the technical scheme adopted by the embodiment of the application is as follows: In one aspect of the embodiments of the present application, a femtosecond oscillator is provided, including a pump source system and a femtosecond oscillation module, the femtosecond oscillation module includes a linear mamyshov oscillator, and a holmium-doped fluoride fiber and a tapered fiber disposed between the linear mamyshov oscillators, the linear mamyshov oscillator is composed of a first reflective diffraction grating and a second reflective diffraction grating disposed at a littrow angle, respectively, and a pump beam coupled by the pump source system is incident on the holmium-doped fluoride fiber to generate a laser gain, and the gain laser oscillates between the first reflective diffraction grating and the second reflective diffraction grating through the tapered fiber to expand the spectrum, so that the expanded laser beam covers the reflection wavelengths of the first reflective diffraction grating and the second reflective diffraction grating. In one possible implementation of the embodiment of the present application, the pump source system includes a signal generator, a laser diode driver, and a visible light band laser diode, where the signal generator outputs a periodic signal to the laser diode driver to drive the visible light band laser diode to pulse out, or the signal generator outputs a direct current signal to the laser diode driver to drive the visible light band laser diode to output a continuous wave. In one possible implementation of the embodiment of the present application, the visible light band laser diode is a blue laser diode. In a possible implementation manner of the embodiment of the present application, the femto-second oscillator further includes a pump optical coupling module disposed between the pump source system and the femto-second oscillation module, the pump optical coupling module includes at least one convex lens, a dichroic mirror is further disposed in the femto-second oscillation module, and after the pump optical coupling module collimates and focuses the pump light beam, the pump light beam is coupled into the holmium-doped fluoride optical fiber through the dichroic mirror. In a possible implementatio