Method and apparatus for generating ultrashort light pulses

• US 4,972,423 A
• Filed: 12/30/1988
• Issued: 11/20/1990
• Est. Priority Date: 12/30/1988
• Status: Expired due to Fees

• Current Assignee: Delfyett, Peter J., Dorsinville, Roger, Robert R. Alfano
• Original Assignee: Delfyett, Peter J., Dorsinville, Roger, Robert R. Alfano
• Inventors: Delfyett, Peter J., Dorsinville, Roger, Alfano, Robert R.
• Primary Examiner(s): Scott, Jr., Leon
• Application Number:
  US07/292,185
• Time in Patent Office: 690 Days
• Field of Search: 372/25, 372/18, 372/102, 372/20, 372/33, 372/69, 372/92, 372/93, 356/301
• US Class Current: 372/25
• 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 3/30 using scattering effects, e.g. stimulated Brillouin or Raman effects

Abstract

A method and apparatus for generating a light pulse having a duration as short as about 3 picoseconds is disclosed. A 5 mJ 25 picosecond second harmonic light pulse from a Nd:YAG laser system is focused into a 5 cm cell filled with D₂ O so as to generate a continuum light pulse spanning about 150 nanometers with an average energy of at least 20 nd/nm across the spectrum. The continuum light pulse is fed through a 10 nanometer narrowband filter centered at 580 nanometers, producing an output pulse having a duration of about 3 picoseconds. The pulse so produced has a number of uses including as a seed pulse for dye laser oscillators and solid state amplifiers or as a pump source for pumping ultrashort dye lasers.

Claims

1. A method of generating a shortened ultrafast laser light pulse comprising:

a. generating an ultrafast laser light pulse,

b. generating a broadband light continuum pulse from the ultrafast laser light pulse, and then

c. passing the broadband light continuum pulse through a tunable spectral selector, thereby producing a pulse within a selected region of the broadband light continuum pulse, resulting in a pulse constituting a shortened ultrafast laser light pulse.

2. The method of claim 1 and further including amplifying the resulting shortened ultrafast laser light pulse and then generating a broadband continuum pulse from the amplified resulting shortened ultrafast laser light pulse.

3. A method of shortening the duration of an ultrashort light pulse comprising:

a. generating a broadband continuum light pulse from the ultrashort light pulse, the broadband continuum light pulse having a duration corresponding to that of the ultrashort light pulse, and then

b. passing the broadband continuum light pulse through a tunable spectral selector wherein a pulse is produced corresponding to a selected spectral region of the broadband continuum pulse, said resulting pulse having a duration less than that of the ultrashort light pulse.

4. Apparatus for use in generating a shortened ultrafast laser light pulse comprising:

a. means for generating an ultrafast laser light pulse,

b. a continuum generator for generating a broadband light continuum pulse from the ultrafast laser light pulse, and

c. tunable means for removing from the broadband continuum light pulse all frequencies except those over a preselected spectral region and producing as a result thereof a shortened ultrafast laser light pulse.

5. The apparatus of claim 4 and further including means for amplifying the shortened ultrafast laser light pulse and means for generating a broadband continuum from the amplified shortened ultrafast laser light pulse.

6. The apparatus of claim 4 and wherein the continuum generator comprises a nonlinear solid or a nonlinear liquid.

7. The apparatus of claim 4 and wherein the continuum generator is either D₂ O or glass or CC1₄.

8. The apparatus of claim 4 and wherein the tunable means includes a filter.

9. The apparatus of claim 4 and wherein the tunable means includes a grating.

10. The apparatus of claim 4 and wherein the tunable means includes a spectrometer.

11. The apparatus of claim 4 and wherein the means for generating an ultrafast laser light pulse comprises a mode locked laser.

12. The apparatus of claim 4 and wherein the tunable means includes a combination of filters.

13. Apparatus for producing a light pulse of about 3 picoseconds comprising:

a. means for producing a pulse of light having a duration of about 25 picoseconds.

b. means for generating a broadband continuum from the pulse of light, the broadband continuum spanning a region of about 150 nanometers, and

c. tunable means for removing from the broadband continuum all frequencies except those over a preselected 10 nanometer spectral region, the pulse duration of the 10 nanometer spectral region being about 3 picoseconds.