What is claimed is:
1. A high intensity eye safe laser, comprising:
an optical parametric oscillator;
an optical parametric amplifier; and,
a pumping source, said oscillator, amplifier and pumping source located on a single beam line.
2. The laser of claim 1, wherein said pumping source outputs 1.0 micron pumping pulses.
3. The laser of claim 2, wherein said pumping pulses first pump said optical parametric oscillator, followed by pumping said optical parametric amplifier.
4. The laser of claim 3, wherein a small portion of the energy of a pumping pulse is first absorbed by said oscillator, leaving enough energy to pump said amplifier.
5. The laser of claim 4, wherein said pulses have a pulse length in excess of 15 nanoseconds.
6. The laser of claim 1, wherein said oscillator and said amplifier each include at least one non-linear crystal.
7. The laser of claim 6, wherein said crystals include KTP crystals.
8. The laser of claim 7, wherein said pumping source includes a neodynium YAG laser.
9. A method for increasing the range of an eye safe laser so that the laser can be used where these may be humans present, comprising the steps of:
generating an eye safe laser output from an optical parametric oscillator; and,
amplifying the output of the optical parametric oscillator with an optical parametric amplifier.
10. The method of claim 9, wherein the oscillator and amplifier are pumped from the same source.
11. The method of claim 10, wherein the oscillator, amplifier and pumping source lie on a single beam line, thus to eliminate dual pumping and synchronization of the pumping of the oscillator and the amplifier.
12. The method of claim 9, wherein the eye safe laser is used for laser target designation.
13. The method of claim 9, wherein the eye safe laser is used for target illumination.
14. The method of claim 9, wherein the beam width of the laser beam produced by the eye safe laser has a beam quality of 24 mm-milliradians.
15. A method of extending the range of an eye safe laser without widening the beam width or synchronizing pumping pulses, comprising the steps of:
generating an eye safe laser beam using an optical parametric oscillator;
amplifying the output of the optical parametric oscillator with an optical parametric amplifier; and,
pumping both the oscillator and the amplifier with the same pumping pulse from a pumping laser.
16. The method of claim 15, wherein the amplifier, the oscillator and the pumping laser are on a single beam line.
17. The method of claim 16, wherein the pumping laser laser emits radiation at 1.0 microns and wherein the oscillator has an output at 1.5 microns.
18. The method of claim 17, wherein the oscillator has a cavity defined by input and output mirrors and wherein the mirrors are coated so as to suppress any output other than 1.5 micron radiation.
19. A method of extending the range of a laser without widening the beam width or synchronizing pumping pulses, comprising the steps of:
generating a laser beam using an optical parametric oscillator;
amplifying the output of the optical parametric oscillator with an optical parametric amplifier; and,
pumping both the oscillator and the amplifier with the same pumping pulse from a pumping laser.
20. A high intensity laser comprising in combination:
an optical parametric oscillator;
an optical parametric amplifier; and,
a pumping source, said oscillator, amplifier and pumping source located on a single beam line, the pumping source energy that pumps said oscillator pumping said amplifier after passing through said oscillator.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A system for measuring an RF input signal frequency, comprising:
a sampling optical pulse train with a frequency-dithered repetition-rate; and
a sub-sampled analog link coupled to the optical pulse train whereby the RF input signal frequency is determined.
2. The system of claim 1, wherein the RF input signal frequency is determined by applying thereto the frequency-dithered repetition-rate and then measuring the amplitude of modulation sidebands relative to the RF input signal’s aliased signal amplitude.
3. The system of claim 2, wherein an alias band of the RF input signal is directly determined by measuring the sidelobe-to-peak ratio (SPR) and comparing with that computed from the equation
SPR
sig
=
SPR
comb
=
SPR
=
(
n
2
\ue89e
\u03ba
\ue89e
\ue89e
V
j
f
j
)
2
where \u03ba is the FM sensitivity (kHzV) of the synthesizer driving the comb source, Vj is the amplitude of the FM control voltage, and \u03c9j2\u03c0=fj is the FM frequency.
4. A method for measuring an RF signal input frequency, comprising:
optically sampling the RF signal;
applying thereto a frequency-dithered repetition-rate; and
measuring the amplitude of modulation sidebands relative to the RF input signal’s aliased signal amplitude whereby the RF input signal frequency is determined.
5. The method of claim 4 wherein the optical sampling is conducted via a Mach-Zehnder intensity modulator and the RF signal is recovered by direct detection of the modulated optical pulse train with a photodiode.
6. The method of claim 4, wherein the RF input signal frequency is determined by measuring the amplitude of modulation sidebands relative to the RF input signal’s aliased signal amplitude.
7. The method of claim 6, wherein an alias band of the RF input signal is directly determined by measuring the sidelobe-to-peak ratio (SPR) and comparing with that computed from the equation
SPR
sig
=
SPR
comb
=
SPR
=
(
n
2
\ue89e
\u03ba
\ue89e
\ue89e
V
j
f
j
)
2
where \u03ba is the FM sensitivity (kHzV) of the synthesizer driving the comb source, Vj is the amplitude of the FM control voltage, and \u03c9j2\u03c0=fj is the FM frequency.
8. The method of claim 4, wherein the optical sampling is performed from a source selected from the group consisting of an optical comb, a tunable-rate actively-modelocked laser, and a mode-locked laser with a known timing jitter.
9. The method of claim 4, wherein the phase-dither is a waveform selected from the group consisting of a simple sinusoidal phase-modulation, a chirped waveform, and a phase-encoded digital waveform.