RESUMO
Optical properties of nanostructures depend on size, shape, material, and local environment. These characteristics can be probed interferometrically, given a broadband source. However, broadband supercontinuum sources are intrinsically noisy, limiting the measurement sensitivity. In this article we describe the application of an auto-balancing technique to reduce the noise in a broadband supercontinuum source, thus increasing the signal to noise ratio. We show a noise reduction of 41 dB allowing optical powers as small as 0.01 pW to be interferometrically detected with a 5 ms integration time.
RESUMO
A continuous-wave all-polarization maintaining ytterbium-doped fiber master oscillator power amplifier, with a tuning range of 70 nm addressable at tuning rates of up to 20 nm/ms, is described. Up to 10 W of linearly polarized output was generated with an amplified spontaneous emission content of less than 0.2% throughout the tuning range.
RESUMO
We report the realization of a singly resonant optical parametric oscillator (SRO) that is designed to provide narrow-bandwidth, continuously tunable radiation at a wavelength of 1163 nm for optical cooling of osmium ions. The SRO is based on periodically poled, magnesium-oxide-doped lithium niobate and pumped at 532 nm. The output coupling of the resonant idler wave is adjusted to yield up to 400 mW of 1163 nm radiation, with a bandwidth of a few megahertz. For continuous frequency tuning of the idler wave, the SRO is equipped with an intracavity etalon, and the cavity length is controlled with a piezo-actuated mirror synchronized to the etalon angle.
RESUMO
We report a singly resonant optical parametric oscillator (SRO) based on a ZnGeP(2) crystal directly pumped by a lamp-pumped Q-switched CrTmHo:YAG laser. The IR was tunable from 4.7 to 7.8 microm via crystal angle tuning. A maximum optical to optical efficiency of 56% was obtained from the pump (2.09 microm) to total IR at a pump energy of 6.5 mJ. The corresponding idler energy was 1.45 mJ. The SRO was measured to have a slope efficiency of 64% and a threshold of 1 mJ. The spatial beam quality of the idler, characterized by the M(2) parameter, was 1.38 when the SRO was pumped at 2.5 times threshold. These results show that ZnGeP(2) optical parametric oscillators directly pumped by a CrTmHo:YAG laser can be operated efficiently, while maintaining good IR beam quality.
RESUMO
We describe the implementation of the wavelength- and frequency-modulation spectroscopy techniques using a singly-resonant optical parametric oscillator (OPO) pumped by a fiber-amplified diode laser. Frequency modulation of the diode laser was transferred to the OPO's mid-infrared idler output, avoiding the need for external modulation devices. This approach thus provides a means of implementing these important techniques with powerful, widely tunable, mid-infrared sources while retaining the simple, flexible modulation properties of diode lasers.
RESUMO
We describe a compact all-solid-state continuous-wave, singly resonant optical parametric oscillator (SRO) based on periodically poled RbTiOAsO4. The SRO is pumped at 1.064 microm by a Nd:YVO4 laser, which is itself pumped by a 3-W diode laser. Using the intracavity technique produced an oscillation threshold for the SRO of only 1.6 W (diode-laser power). For 3 W of diode pump power some 65 mW was obtained in the (nonresonant) idler (wavelength 3.52 microm). Temperature tuning over the range 10-100 degrees C resulted in tuning ranges of 1.52-1.54 and 3.41-3.54 microm for the signal and the idler waves, respectively. Importantly, relaxation oscillations were absent.
RESUMO
We report extended mode-hop-free tuning in a continuous-wave, pump-enhanced optical parametric oscillator (PE-OPO). We employ a dual-cavity configuration to allow independent control of the resonant pump and signal fields, and so we can suppress frequent mode hops in the signal as the pump is tuned in frequency. With the signal field clamped in frequency by an uncoated etalon, the idler field can be scanned smoothly through a range of 10.8 GHz. The PE-OPO outputs can also be tuned coarsely from 1.01 to 1.18 mum in the signal and from 2.71 to 3.26 mum and 4.07 to 5.26 mum in the idler. We find that increased idler absorption only slightly increases the oscillation threshold.
RESUMO
The performance characteristics of a doubly (signal and idler) resonant continuous-wave optical parametric oscillator based on periodically poled lithium niobate and pumped by a 100-mW single-mode laser diode at 810 nm are reported. Pump power thresholds as low as 16 mW and wavelength tuning over the range 1.15-1.25 microm at the signal and 2.31-2.66 microm at the idler were achieved through variation of crystal temperature, pump wavelength, and grating period. Up to 5 mW of signal output was obtained with the single-mode diode pump, and signal powers of up to 39 mW were obtained when pumping with a 400-mW injection-locked broad-area diode laser.
RESUMO
The efficient, low-threshold operation of a 946-nm Nd:YAG laser pumped by an injection-locked broad-area diode laser is reported. The implications of pump-beam quality for efficient, low-threshold operation, particularly with intrinsically inefficient transitions, are discussed in the context of previously published models. Results are presented showing that the M(2) = 1.3 pump beam of the injection-locked diode laser enabled a cw slope efficiency of 48% and a threshold of 52 mW to be attained. When Q-switched, 335 mW of pump power gave 27-ns, 5.2-muJ pulses. These were frequency doubled to obtain 19-ns, 1-muJ pulses at 473 nm. These results represent significant improvements over similar systems pumped by free-running broad-area diode lasers or arrays.
