Method and apparatus for ultra-violet-wavelength laser-induced fluorescence (UV-LIF) using optical output from a photonic-crystal rod

• US 7,751,118 B1
• Filed: 05/28/2006
• Issued: 07/06/2010
• Est. Priority Date: 07/29/2005
• Status: Active Grant

• Current Assignee: Lockheed Martin Aculight Corp. (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Di Teodoro, Fabio, Brooks, Christopher D.
• Primary Examiner(s): Hellner; Mark
• Application Number:
  US11/420,754
• Time in Patent Office: 1,500 Days
• Field of Search: 359/333, 359/341.1, 372/6
• US Class Current: 359/333
• CPC Class Codes: C03B 37/10 Non-chemical treatment surface treatment of fibres or filaments made from glass, minerals or slags C03C25/00
• CPC Class Codes: G02B 6/02328 Hollow or gas filled core
• CPC Class Codes: G02B 6/02347 Longitudinal structures arranged to form a regular periodic lattice, e.g. triangular, square, honeycomb unit cell repeated throughout cladding
• CPC Class Codes: G02B 6/02376 Longitudinal variation along fibre axis direction, e.g. tapered holes
• CPC Class Codes: G02B 6/02385 Comprising liquid, e.g. fluid filled holes
• CPC Class Codes: G02B 6/3826 characterised by form or shape
• CPC Class Codes: G02B 6/3853 Lens inside the ferrule lensed connectors G02B6/32
• 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 3/0064 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 3/06704 Housings; Packages
• CPC Class Codes: H01S 3/06708 Constructional details of the fibre, e.g. compositions, cross-section, shape or tapering optical fibres as passive waveguides G02B6/02
• CPC Class Codes: H01S 3/06729 Peculiar transverse fibre profile
• CPC Class Codes: H01S 3/06741 Photonic crystal fibre, i.e. the fibre having a photonic bandgap
• CPC Class Codes: H01S 3/06745 Tapering of the fibre, core or active region
• CPC Class Codes: H01S 3/06754 Fibre amplifiers H01S3/06708 takes precedence
• CPC Class Codes: H01S 3/06758 Tandem amplifiers
• CPC Class Codes: H01S 3/094007 Cladding pumping, i.e. pump light propagating in a clad surrounding the active core

Abstract

A method and apparatus use a photonic-crystal fiber having a very large core while maintaining a single transverse mode. In some fiber lasers and amplifiers having large cores problems exist related to energy being generated at multiple-modes (i.e., polygamy), and of mode hopping (i.e., promiscuity) due to limited control of energy levels and fluctuations. The problems of multiple-modes and mode hopping result from the use of large-diameter waveguides, and are addressed by the invention. This is especially true in lasers using large amounts of energy (i.e., lasers in the one-megawatt or more range). By using multiple small waveguides in parallel, large amounts of energy can be passed through a laser, but with better control such that the aforementioned problems can be reduced. An additional advantage is that the polarization of the light can be maintained better than by using a single fiber core.

Claims

1. An apparatus comprising:

an optical transmitter component configured for use in a long-range optical measuring device, the component including;

a signal laser that emits a laser signal;

a first photonic-crystal optical device operatively coupled to receive the signal laser signal, the photonic-crystal optical amplifier device including a signal waveguide that has a diameter of at least 40 microns and maintains a single transverse mode, and

at least one wavelength-conversion optical medium operable to receive high-peak-power input radiation having a first wavelength from the signal waveguide of the first photonic-crystal device and to generate radiation having a peak power of at least about 100 kW and a second wavelength that is shorter than 400 nm through wavelength conversion.

2. The apparatus of claim 1, wherein the wavelength-conversion optical medium includes at least one non-linear frequency doubler.

3. The apparatus of claim 1, wherein the wavelength-conversion optical medium includes an optical parametric oscillator.

4. The apparatus of claim 1, further comprising:

a detector configured to detect ultra-violet-wavelength laser-induced-fluorescence (UV-LIF), wherein the first photonic-crystal optical device is operated as part of an optical transmitter within a device that directs the optical beam towards an airborne cloud material to be analyzed; and

an analysis unit configured to detect specific substances.

5. The apparatus of claim 1, wherein the analysis unit is configured to analyze inorganic chemicals.

6. The apparatus of claim 1, wherein the analysis unit is configured to analyze organic chemicals.

7. The apparatus of claim 1, wherein the analysis unit is configured to analyze biological compounds.

8. A method comprising:

obtaining a pulsed laser signal;

amplifying the signal laser signal using a photonic-crystal optical amplifier device that includes a signal waveguide that has a diameter of at least 40 microns and maintains a single transverse mode and generates, high-peak-power pulsed radiation; and

wavelength-converting the high-peak-power pulsed radiation having a first wavelength from the signal waveguide of the photonic-crystal device to generate radiation having a peak power of at least about 100 kW and a second wavelength that is shorter than 400 nm.

9. The method of claim 8, wherein the wavelength-converting includes at least one non-linear frequency doubling.

10. The method of claim 8, wherein the wavelength-converting includes optical parametric oscillating.

11. The method of claim 8, further comprising:

optically transmitting the optical beam towards an airborne cloud material to be analyzed;

detecting ultra-violet-wavelength laser-induced-fluorescence (UV-LIF); and

analyzing the detected UV-LIF to detect specific substances.

12. The method of claim 8, wherein the analyzing is configured to analyze inorganic chemicals.

13. The method of claim 8, wherein the analyzing is configured to analyze organic chemicals.

14. The method of claim 8, wherein the analyzing is configured to analyze biological compounds.

15. An apparatus comprising:

an optical transmitter component configured for use in a long-range optical measuring device, the component including;

a signal laser that emits a laser signal;

photonic-crystal means for amplifying the signal laser signal having a signal waveguide that has a diameter of at least 40 microns and maintains a single transverse mode and that generates high-peak-power pulsed radiation having a first wavelength; and

means for wavelength-converting the high-peak-power pulsed radiation to generate radiation having a peak power of at least about 100 kW and a second wavelength that is wavelength shorter than 400 nm.

16. The apparatus of claim 15, wherein the means for wavelength-converting includes at least one non-linear means for frequency doubling.

17. The apparatus of claim 15, wherein the means for wavelength-converting includes an optical parametric oscillator.

18. The apparatus of claim 15, further comprising:

means for optically transmitting the optical beam towards an airborne cloud material to be analyzed;

means for detecting ultra-violet-wavelength laser-induced-fluorescence (UV-LIF); and

means for analyzing the detected UV-LIF to detect specific substances.

19. The apparatus of claim 15, wherein the means for analyzing is configured to analyze inorganic chemicals.

20. The apparatus of claim 15, wherein the means for analyzing is configured to analyze organic chemicals.

21. The apparatus of claim 15, wherein the means for analyzing is configured to analyze biological compounds.