111 research outputs found
-BaBO deep UV monolithic walk-off compensating tandem
The generation of watt-level cw narrow-linewidth sources at specific deep UV
wavelengths corresponding to atomic cooling transitions usually employs
external cavity-enhanced second-harmonic generation (SHG) of moderate-power
visible lasers in birefringent materials. In this work, we investigate a novel
approach to cw deep-UV generation by employing the low-loss BBO in a monolithic
walkoff-compensating structure [Zondy {\it{et al}}, J. Opt. Soc. Am. B
{\bf{20}} (2003) 1675] to simultaneously enhance the effective nonlinear
coefficient while minimizing the UV beam ellipticity under tight focusing. As a
preliminary step to cavity-enhanced operation, and in order to apprehend the
design difficulties stemming from the extremely low acceptance angle of BBO, we
investigate and analyze the single-pass performance of a mm monolithic
walk-off compensating structure made of 2 optically-contacted BBO plates cut
for type-I critically phase-matched SHG of a cw nm dye laser. As
compared with a bulk crystal of identical length, a sharp UV efficiency
enhancement factor of 1.65 has been evidenced with the tandem structure, but at
nm from the targeted fundamental wavelength, highlighting the
sensitivity of this technique when applied to a highly birefringent material
such as BBO. Solutions to angle cut residual errors are identified so as to
match accurately more complex periodic-tandem structure performance to any
target UV wavelength, opening the prospect for high-power, good beam quality
deep UV cw laser sources for atom cooling and trapping.Comment: 21 pages, 8 figures, to appear in Opt. Commu
75%-efficiency blue generation from an intracavity PPKTP frequency doubler
We report on a high-efficiency 461 nm blue light conversion from an external
cavity-enhanced second-harmonic generation of a 922 nm diode laser with a
quasi-phase-matched KTP crystal (PPKTP). By choosing a long crystal (LC=20 mm)
and twice looser focusing (w0=43 m) than the "optimal" one, thermal
lensing effects due to the blue power absorption are minimized while still
maintaining near-optimal conversion efficiency. A stable blue power of 234 mW
with a net conversion efficiency of eta=75% at an input mode-matched power of
310 mW is obtained. The intra-cavity measurements of the conversion efficiency
and temperature tuning bandwidth yield an accurate value d33(461 nm)=15 pm/V
for KTP and provide a stringent validation of some recently published linear
and thermo-optic dispersion data of KTP
Stability of the self-phase-locked pump-enhanced singly resonant parametric oscillator
Steady-state and dynamics of the self-phase-locked (3\omega ==> 2\omega,
\omega) subharmonic optical parametric oscillator are analyzed in the
pump-and-signal resonant configuration, using an approximate analytical model
and a full propagation model. The upper branch solutions are found always
stable, regardless of the degree of pump enhancement. The domain of existence
of stationary states is found to critically depend on the phase-mismatch of the
competing second-harmonic process.Comment: LateX2e/RevteX4, 4 pages, 5 figures. Submitted to Phys. Rev. A
(accepted on Jan. 17, 2003
Sum-frequency generation of 589 nm light with near-unit efficiency
We report on a laser source at 589 nm based on sum-frequency generation of
two infrared laser at 1064 nm and 1319 nm. Output power as high as 800 mW are
achieved starting from 370 mW at 1319 nm and 770 mW at 1064 nm, corresponding
to converting roughly 90% of the 1319 nm photons entering the cavity. The power
and frequency stability of this source are ideally suited for cooling and
trapping of sodium atoms
A phase-locked frequency divide-by-3 optical parametric oscillator
Accurate phase-locked 3:1 division of an optical frequency was achieved, by
using a continuous-wave (cw) doubly resonant optical parametric oscillator. A
fractional frequency stability of 2*10^(-17) of the division process has been
achieved for 100s integration time. The technique developed in this work can be
generalized to the accurate phase and frequency control of any cw optical
parametric oscillator.Comment: 4 pages, 5 figures in a postscript file. To appear in a special issue
of IEEE Trans. Instr. & Meas., paper FRIA-2 presented at CPEM'2000
conference, Sydney, May 200
Optical, vibrational, thermal, electrical, damage and phase-matching properties of lithium thioindate
Lithium thioindate (LiInS) is a new nonlinear chalcogenide biaxial
material transparent from 0.4 to 12 m, that has been successfully grown in
large sizes and good optical quality. We report on new physical properties that
are relevant for laser and nonlinear optics applications. With respect to
AgGaS(e) ternary chalcopyrite materials, LiInS displays a
nearly-isotropic thermal expansion behavior, a 5-times larger thermal
conductivity associated with high optical damage thresholds, and an extremely
low intensity-dependent absorption allowing direct high-power downconversion
from the near-IR to the deep mid-IR. Continuous-wave difference-frequency
generation (5-11m) of Ti:sapphire laser sources is reported for the first
time.Comment: 27 pages, 21 figures. Replaces the previous preprint
(physics/0307082) with the final version as it will be published in J. Opt.
Soc. Am. B 21(11) (Nov. 2004 issue
Quantum measurement of the degree of polarization of a light beam
We demonstrate a coherent quantum measurement for the determination of the
degree of polarization (DOP). This method allows to measure the DOP in the
presence of fast polarization state fluctuations, difficult to achieve with the
typically used polarimetric technique. A good precision of the DOP measurements
is obtained using 8 type II nonlinear crystals assembled for spatial walk-off
compensation.Comment: 4 pages, 3 figure
Generating green to red light with semiconductor lasers
Diode lasers enable one to continuously cover the 730 to 1100 nm range as
well as the 370 to 550 nm range by frequency doubling, but a large part of the
electro-magnetic spectrum spanning from green to red remains accessible only
through expensive and unpractical optically pumped dye lasers. Here we devise a
method to multiply the frequency of optical waves by a factor 3/2 with a
conversion that is phase-coherent and highly efficient. Together with harmonic
generation, it will enable one to cover the visible spectrum with semiconductor
lasers, opening new avenues in important fields such as laser spectroscopy and
optical metrology.Comment: to be published on Optics Expres
Line intensity measurements of methane’s ν3-band using a cw-OPO
We report on absolute line strength measurements of P(1), R(0) and R(1) singlet lines in the 3:3 μm ν3 (C–H stretching) band of methane 12CH4 at referencetemperature T = 296 K. Line strength measurements are performed at low pressure (P <1 Torr) using direct absorption spectroscopy technique based on a widely tunable continuous-wave singly resonant optical parametric oscillator. The 1σ overall accuracy in line strength determinations ranges between 7 and 8 % mostly limited by pressure and frequency measurements. A comparison with previous reported values is made. Our results show good agreement with the HITRAN 2012 database
Quantum Mirrors and Crossing Symmetry as Heart of Ghost Imaging
In this paper it is proved that the key to understanding the ghost imaging
mystery are the crossing symmetric photon reactions in the nonlinear media.
Hence, the laws of the plane quantum mirror (QM) and that of spherical quantum
mirror, observed in the ghost imaging experiments, are obtained as natural
consequences of the energy-momentum conservation laws. So, it is shown that the
ghost imaging laws depend only on the energy-momentum conservation and not on
the photons entanglement. The extension of these results to the ghost imaging
with other kind of light is discussed. Some fundamental experiments for a
decisive tests of the [SPDC-DFG]-quantum mirror are suggested.Comment: 11 pages, 9 figure
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