US 12,080,984 B2
Apparatus and method for tunable frequency parametric down conversion of high peak power lasers through dual chirp pulse mixing
Michael H. Helle, Arlington, VA (US)
Assigned to The Government of the United States of America, as represented by the Secretary of the Navy, Arlington, VA (US)
Filed by The Government of the United States of America, as represented by the Secretary of the Navy, Arlington, VA (US)
Filed on Aug. 26, 2021, as Appl. No. 17/412,339.
Application 17/412,339 is a division of application No. 16/662,166, filed on Oct. 24, 2019, granted, now 11,133,637.
Claims priority of provisional application 62/750,845, filed on Oct. 26, 2018.
Prior Publication US 2021/0384692 A1, Dec. 9, 2021
Int. Cl. H01S 3/00 (2006.01); G02B 5/18 (2006.01); G02F 1/39 (2006.01); H01S 3/1106 (2023.01)
CPC H01S 3/0057 (2013.01) [G02B 5/1819 (2013.01); G02F 1/39 (2013.01); G02F 1/392 (2021.01); H01S 3/0085 (2013.01); H01S 3/1106 (2013.01)] 7 Claims
OG exemplary drawing
 
1. A tunable pulse stretcher/compressor, comprising:
a first grating and a second grating, each of the first and second gratings having selectively tunable grating features therein; and
a retroreflector;
wherein the first grating is tunably rotatable relative to an incoming laser pulse incident on the first grating, an angle of the grating features in the first grating relative to the incoming laser pulse being tuned via the rotation to form a first plurality of reflected pulses having a corresponding first predetermined plurality of frequencies that travel to the second grating;
wherein the second grating is tunably rotatable relative to the reflected laser pulses incident on the second grating, an angle of the grating features in the second grating relative to the incident reflected laser pulses being tuned via the rotation to form a second plurality of reflected pulses having a corresponding second predetermined plurality of frequencies that travel to the retroreflector, at least one of the second plurality of reflected pulses having a frequency different from a frequency of at least one of the first plurality of reflected pulses;
wherein the retroreflector directs the second plurality of reflected pulses back into the second grating as a third plurality of reflected pulses, wherein a distance between the second grating and the retroreflector is tuned to produce a predetermined chirp in each of the third plurality of reflected pulses;
wherein the third plurality of reflected pulses travel from the second grating to the first grating as a fourth plurality of reflected pulses, each of the third plurality of reflected pulses having a corresponding chirp;
wherein the grating features of the first grating are tuned to combine the fourth plurality of reflected pulses into a predetermined final pulse having a predetermined positive or negative chirp that is output from the stretcher compressor; and
wherein the first and second gratings and the retroreflector are selectively rotatable around an axis of the first grating to enable the ability to vary the laser wavelength while maintaining the pulse compression as well as alignment into and out of the device.