ABSTRACT
An overall quantum conversion efficiency of 7.8% is achieved by intracavity mixing the signal and idler of a 1.064 µm pumped Rb:PPKTP optical parametric oscillator in BaGa4Se7. In this way, a pulse energy of â¼0.71 mJ is generated at â¼7 µm for a repetition rate of 100 Hz. Tuning of the mid-IR radiation is demonstrated by heating of the Rb:PPKTP crystal.
ABSTRACT
A BaGa4Se7 nanosecond optical parametric oscillator (OPO) shows extremely wide idler tunability in the mid-IR (2.7-17 µm) under 1.064 µm pumping. The â¼10 ns pulses at â¼7.2 µm have an energy of 3.7 mJ at 10 Hz. The pump-to-idler conversion efficiency for this wavelength reaches 5.9% with a slope of 6.5% corresponding to a quantum conversion efficiency or pump depletion of 40%.
ABSTRACT
A 1.064 µm pumped Rb:PPKTP optical parametric oscillator (OPO) generates mid-IR radiation by intracavity mixing the resonant signal and idler waves in AgGaSe2. The â¼6 ns pulses at â¼7 µm have an energy of 670 µJ at 100 Hz, equivalent to an average power of 67 mW. The overall quantum conversion efficiency from 1.064 µm amounts to 8%, and the power conversion efficiency is 1.2%.
ABSTRACT
A human exhaled air analysis by means of infrared (IR) laser photoacoustic spectroscopy is presented. Eleven healthy nonsmoking volunteers (control group) and seven patients with chronic obstructive pulmonary disease (COPD, target group) were involved in the study. The principal component analysis method was used to select the most informative ranges of the absorption spectra of patients' exhaled air in terms of the separation of the studied groups. It is shown that the data of the profiles of exhaled air absorption spectrum in the informative ranges allow identifying COPD patients in comparison to the control group.
Subject(s)
Breath Tests/methods , Photoacoustic Techniques/methods , Principal Component Analysis/methods , Pulmonary Disease, Chronic Obstructive/diagnosis , Spectrophotometry, Infrared/methods , Adult , Humans , Male , Middle Aged , Pulmonary Disease, Chronic Obstructive/metabolism , Volatile Organic Compounds/analysis , Volatile Organic Compounds/chemistry , Young AdultABSTRACT
A AgGaSe2 nonlinear crystal placed in a coupled cavity is intracavity pumped by the ~1.85-µm signal pulses of a 1.064-µm pumped Rb:PPKTP doubly-resonant optical parametric oscillator (OPO) operating at a repetition rate of 100 Hz. Using two samples cut for type-I and II phase-matching, the overall idler tunability of the singly-resonant AgGeSe2 OPO covers an unprecedented spectral range from 5.8 to ~18 µm in the mid-IR.
