Laser illumination systems and methods for dual-excitation wavelength non-linear optical microscopy and micro-spectroscopy systems
An illumination system is disclosed for providing dual-excitation wavelength illumination for non-linear optical microscopy and micro-spectroscopy. The illumination system includes a laser system, an optical splitting means, a frequency shifting system, and a picosecond amplifier system. The laser system includes a laser for providing a first train of pulses at a center optical frequency ω 1 . The optical splitting means divides the first train of pulses at the center optical frequency ω 1 into two trains of pulses. The frequency shifting system shifts the optical frequency of one of the two trains of pulses to provide a frequency shifted train of pulses. The picosecond amplifier system amplifies the frequency shifted train of pulses to provide an amplified frequency-shifted train of pulses having a pulse duration of at least 0.5 picoseconds.
1. An illumination system for providing dual-excitation wavelength illumination for non-linear optical microscopy and micro-spectroscopy, said illumination system comprising:
a laser system including a laser oscillator for providing a first train of pulses at a center optical frequency ω 1 ;
an optical splitting means for dividing the first train of pulses at the center optical frequency ω 1 into a first split train of pulses and a second split train of pulses;
a frequency shifting system for shifting the optical frequency of the first split train of pulses to provide a frequency shifted train of pulses; and
a picosecond amplifier system for amplifying the frequency shifted train of pulses to provide an amplified frequency-shifted train of pulses having a pulse duration of at least 0.5 picoseconds.
2. The illumination system as claimed in claim 1 , wherein said picosecond amplifier is a narrowband amplifier.
3. The illumination system as claimed in claim 2 , wherein said narrowband amplifier is tunable to provide that the difference frequency of the amplified frequency-shifted train of pulses and the second split train of pulses may be varied.
4. The illumination system as claimed in claim 2 , wherein said narrowband amplifier system includes a narrowband filter.
5. The illumination system as claimed in claim 2 , wherein said narrowband amplifier system includes a plurality of amplifiers in series.
6. The illumination system as claimed in claim 1 , wherein said laser system includes a high power oscillator.
7. The illumination system as claimed in claim 1 , wherein said laser system includes a low power oscillator and an amplifier.
8. The illumination system as claimed in claim 1 , wherein said illumination system further includes a laser amplifier for amplifying the second split train of pulses.
9. The illumination system as claimed in claim 1 , wherein said frequency shifting system includes a highly non-linear fiber.
10. The illumination system as claimed in claim 1 , wherein said frequency shifting system includes a photonic crystal fiber.
11. The illumination system as claimed in claim 1 , wherein said frequency shifting system further includes a laser amplifier.
12. The illumination system as claimed in claim 1 , wherein said picosecond amplifier is a chirp amplifier to provide an amplified frequency-shifted train of pulses having pulses with a temporally evolving instantaneous frequency over the picosecond pulse duration.
13. The illumination system as claimed in claim 12 , wherein said chirped amplifier system includes a chirp unit and an amplifier.
14. The illumination system as claimed in claim 13 , wherein said chirped amplifier system further includes a broadband filter.
15. The illumination system as claimed in claim 14 , wherein system further includes a chirp control system in the second split train of pulses.
16. The illumination system as claimed in claim 1 , wherein system further includes:
a combiner for combining the amplified frequency-shifted train of pulses and the second split train of pulses from the optical splitting means; and
adjusting means for adjusting a time delay between the amplified frequency-shifted train of pulses and the second split train of pulses with sub-picosecond precision to provide a collinear output of the dual-excitation wavelength illumination for the non-linear optical microscopy or micro-spectroscopy system.
17. The illumination system as claimed in claim 1 , wherein said laser system is one of a Ytterbium fiber laser and an Erbium fiber laser.
18. The illumination system as claimed in claim 1 , wherein said laser system is a Titanium Sapphire laser.
19. The illumination system as claimed in claim 1 , wherein said picosecond amplifier system is one of an Erbium fiber amplifier, a Ytterbium fiber amplifier, a Thulium fiber amplifier, and a Holmium fiber amplifier.
20. The illumination system as claimed in claim 1 , wherein the output of the picosecond amplifier system is frequency doubled (SHG) or tripled (THG).
21. The illumination system as claimed in claim 1 , wherein the second split train of pulses from the optical splitting means is frequency doubled (SHG) or tripled (THG).