Femtosecond laser processing system with process parameters controls and feedback

• US 9,774,160 B2
• Filed: 08/27/2015
• Issued: 09/26/2017
• Est. Priority Date: 03/31/2004
• Status: Active Grant

• Current Assignee: IMRA America Incorporated (Aisin Corp.)
• Original Assignee: IMRA America Incorporated (Aisin Corp.)
• Inventors: Harter, Donald J.
• Primary Examiner(s): NGUYEN, DUNG T
• Application Number:
  US14/837,619
• Publication Number:
  US 20150372445A1
• Time in Patent Office: 761 Days
• CPC Class Codes: G01J 11/00 Measuring the characteristics of individual optical pulses or of optical pulse trains
• CPC Class Codes: H01S 3/0014 Monitoring arrangements not otherwise provided for photometry G01J1/00, e.g. G01J1/4257; radiation pyrometry G01J5/00; measuring coherence of light G01J9/00; measuring wavelength of light G01J9/00, e.g. G01J9/0246; measuring optical pulses G01J11/00; calorimetrically measuring power of laser beams G01K17/003
• CPC Class Codes: H01S 3/005 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 shaping laser beam for working metal or other materials B23K26/06; optical elements, systems or apparatus in general G02B
• CPC Class Codes: H01S 3/0057 Temporal shaping, e.g. pulse compression, frequency chirping soliton generation and propagation G02F1/3513, H01S3/063 and H01S3/108
• CPC Class Codes: H01S 3/0064 Anti-reflection devices, e.g. optical isolaters absorbing layers for marking or protecting purposes in laser working B23K26/50; magneto-optical non-reciprocal devices G02F1/093, G02F1/0955
• CPC Class Codes: H01S 3/0078 Frequency filtering
• CPC Class Codes: H01S 3/06754 Fibre amplifiers H01S3/06708 takes precedence
• CPC Class Codes: H01S 3/10023 by functional association of additional optical elements, e.g. filters, gratings, reflectors
• CPC Class Codes: H01S 3/10038 Amplitude control
• CPC Class Codes: H01S 3/10061 Polarization control
• CPC Class Codes: H01S 3/102 by controlling the active medium, e.g. by controlling the processes or apparatus for excitation H01S3/13 takes precedence
• CPC Class Codes: H01S 3/1024 for pulse generation
• CPC Class Codes: H01S 3/108 using non-linear optical devices, e.g. exhibiting Brillouin or Raman scattering mode locking using a non-linear element H01S3/1112
• CPC Class Codes: H01S 3/109 Frequency multiplication, e.g. harmonic generation
• CPC Class Codes: H01S 3/1305 Feedback control systems
• CPC Class Codes: H01S 3/1618 ytterbium

Abstract

A femtosecond laser based laser processing system having a femtosecond laser, frequency conversion optics, beam manipulation optics, target motion control, processing chamber, diagnostic systems and system control modules. The femtosecond laser based laser processing system allows for the utilization of the unique heat control in micromachining, and the system has greater output beam stability, continuously variable repetition rate and unique temporal beam shaping capabilities.

Claims

1. A pulse source, comprising:

a seed source configured to emit seed pulses;

a pulse separator disposed downstream from said seed source and configured to receive, as an input pulse, one of said seed pulses emitted by said seed source, said pulse separator configured to temporally separate said input pulse into first and second time separated pulse components, wherein each of said first and second time separated pulse components comprises a pulse energy less than an energy of said input pulse;

at least one fiber amplifier configured to receive and amplify said first and second time separated pulse components and to thereby generate amplified first and second time separated pulse components; and

a pulse recombiner which recombines said amplified first and second time separated pulse components into a reconstructed output pulse having greater pulse energy than said input pulse,

wherein said seed source generates ultrashort pulses.

2. The pulse source according to claim 1, wherein said pulse separator comprises a series of fiber gratings operating on different portions of an input pulse spectrum, and said first and second time separated pulse components comprise spectral components.

3. The pulse source according to claim 1, wherein said pulse recombiner comprises a grating compressor.

4. The pulse source according to claim 3, wherein said grating compressor consists of a single compression grating.

5. The pulse source according to claim 1, wherein said pulse recombiner comprises air separated, bulk glass Bragg grating compressors.

6. The pulse source according to claim 5, further comprising:

a series of fiber gratings operating on different portions of an input pulse spectrum, wherein said air separated, bulk glass Bragg grating compressors are spaced in such a way as to complement said series of fiber gratings, such that said reconstructed output pulse is formed as a single, compressed pulse.

7. The pulse source according to claim 1, wherein said pulse source further comprises an optical modulator disposed between said seed source and said pulse separator.

8. The pulse source according to claim 1, wherein said reconstructed output pulse is formed via incoherent addition of said amplified first and second time separated pulse components.

9. The pulse source according to claim 1, wherein said pulse separator and said pulse recombiner each comprise a polarizing beam splitter.

10. The pulse source according to claim 1, wherein said ultrashort pulses comprise femtosecond pulses.