Long-wave infrared laser-induced breakdown spectroscopy of complex gas molecules in the vicinity of a laser-induced plasma.

Vibration-rotation signatures of intact water and complex organic molecules in vapor phase were detected, identified, and mode-assigned in the long-wave infrared emissions of laser-induced plasma. Time resolved long-wave infrared emissions were also studied to assess the temporal behaviors of these gaseous molecular emitters. The temperatures of these molecular vapors in the hot and transient vapor-plasma plume of the laser-induced plasma were estimated to be well above room temperatures during their existence.

Comparative Long-Wave Infrared Laser-Induced Breakdown Spectroscopy Employing 1-D and 2-D Focal Plane Array Detectors.

Long-wave infrared (LWIR) emissions of laser-induced plasma on solid potassium chloride and acetaminophen tablet surfaces were studied using both a one-dimensional (1-D) linear array detection system and, for the first time, a two-dimensional (2-D) focal plane array (FPA) detection system. Both atomic and molecular infrared emitters in the vicinity of the plasma were identified by analyzing the detected spectral signatures in the infrared region. Time- and space-resolved long-wave infrared emissions were also studied to assess the temporal and spatial behaviors of atomic and molecular emitters in the plasma.

A Study of Wave Confinement and Optical Force in Polydimethlysiloxane-Arylazopyrazole Composite for Photonic Applications.

A refractive index of dielectrics was modified by several methods and was known to have direct influence on optical forces in nanophotonic structures. The present contribution shows that isomerization of photoswitching molecules can be used to regulate refractive index of dielectrics in-situ. In particular, spectroscopic study of a polydimethylsiloxane-arylazopyrazole (PDMS-AAP) composite revealed that refractive index of the composite shifts from 2.

Enhanced mid-infrared emission of Pr ions in solids through a "3-for-1" excitation process - quantified.

Evidence is presented that a "three-for-one" process based on two cross-relaxations between Pr ions efficiently populates the mid-infrared-emitting H manifold in a Pr-doped low-maximum-phonon-energy host. The concentration dependence of infrared fluorescence spectra and lifetimes of polycrystalline Pr:KPbCl initially excited to the F manifolds indicate that the 3500-5500-nm fluorescence becomes strongly favored over shorter-wavelength infrared emission bands in the higher-concentration sample. The strong concentration dependence of the F and H manifold lifetimes suggests that both of these decay by cross-relaxation processes, resulting in more than one ion excited to H for each ion initially excited to F.

In situ chemical analysis of geology samples by a rapid simultaneous ultraviolet/visible/near-infrared (UVN) + longwave-infrared laser induced breakdown spectroscopy detection system at standoff distance.

The standoff detection range of the simultaneous ultraviolet/visible/near-infrared (UVN) + longwave-Infrared (LWIR) Laser Induced Breakdown Spectroscopy (LIBS) detection system has been successfully extended from merely 10 cm to ≥ 1 meter by adopting a reflecting telescope collection scheme and UVN + LWIR LIBS emission signatures were acquired in various atmospheres from soil and mineral samples. This system simultaneously captured emission signatures from atomic, and simple and complex molecular target species existing in or near the same laser-induce plasma plume within micro-seconds. These pioneer standoff measurements of UVN + LWIR LIBS signatures have revealed an abundance of plasma-generated sample molecular emitting species in their vapor state along with atomic ones which gave intense and distinct signature emissions in both UVN (conventional LIBS) and LWIR (LWIR LIBS) spectral regions.

Comprehensive study of solid pharmaceutical tablets in visible, near infrared (NIR), and longwave infrared (LWIR) spectral regions using a rapid simultaneous ultraviolet/visible/NIR (UVN) + LWIR laser-induced breakdown spectroscopy linear arrays detection system and a fast acousto-optic tunable filter NIR spectrometer.

This is the first report of a simultaneous ultraviolet/visible/NIR and longwave infrared laser-induced breakdown spectroscopy (UVN + LWIR LIBS) measurement. In our attempt to study the feasibility of combining the newly developed rapid LWIR LIBS linear array detection system to existing rapid analytical techniques for a wide range of chemical analysis applications, two different solid pharmaceutical tablets, Tylenol arthritis pain and Bufferin, were studied using both a recently designed simultaneous UVN + LWIR LIBS detection system and a fast AOTF NIR (1200 to 2200 nm) spectrometer. Every simultaneous UVN + LWIR LIBS emission spectrum in this work was initiated by one single laser pulse-induced micro-plasma in the ambient air atmosphere.

Comparative studies of long-wave laser-induced breakdown spectroscopy emissions excited at 1.064 µm and eye-safe 1.574 µm.

In this work, comparative long-wave infrared (LWIR) laser-induced breakdown spectroscopy (LIBS) emission studies of two excitation sources: conventional 1.064 μm and eye-safe laser wavelength at 1.574 μm were performed to analyze several widely-used inorganic energetic materials such as ammonium and potassium compounds as well as the organic liquid chemical warfare agent simulant, dimethyl methylphosphate (DMMP).

Long-Wave Infrared (LWIR) Molecular Laser-Induced Breakdown Spectroscopy (LIBS) Emissions of Thin Solid Explosive Powder Films Deposited on Aluminum Substrates.

Thin solid films made of high nitro (NO)/nitrate (NO) content explosives were deposited on sand-blasted aluminum substrates and then studied using a mercury-cadmium-telluride (MCT) linear array detection system that is capable of rapidly capturing a broad spectrum of atomic and molecular laser-induced breakdown spectroscopy (LIBS) emissions in the long-wave infrared region (LWIR; ∼5.6-10 µm). Despite the similarities of their chemical compositions and structures, thin films of three commonly used explosives (RDX, HMX, and PETN) studied in this work can be rapidly identified in the ambient air by their molecular LIBS emission signatures in the LWIR region.

Time resolved long-wave infrared laser-induced breakdown spectroscopy of inorganic energetic materials by a rapid mercury-cadmium-telluride linear array detection system.

A mercury-cadmium-telluride linear array detection system that is capable of rapidly capturing (∼1-5 s) a broad spectrum of atomic and molecular laser-induced breakdown spectroscopy (LIBS) emissions in the long-wave infrared region (LWIR, ∼5.6-10 μm) was recently developed. Similar to the conventional ultraviolet-visible LIBS, a broadband emission spectrum of condensed phase samples covering a 5.

Mid infrared emission spectroscopy of carbon plasma.

Mid infrared time-resolved emission spectra were recorded from laser-induced carbon plasma. These spectra constitute the first study of carbon materials LIB spectroscopy in the mid infrared range. The carbon plasma was induced using a Q-switched Nd: YAG laser.

Rapid long-wave infrared laser-induced breakdown spectroscopy measurements using a mercury-cadmium-telluride linear array detection system.

In this work, we develop a mercury-cadmium-telluride linear array detection system that is capable of rapidly capturing (∼1-5  s) a broad spectrum of atomic and molecular laser-induced breakdown spectroscopy (LIBS) emissions in the long-wave infrared (LWIR) region (∼5.6-10  μm). Similar to the conventional UV-Vis LIBS, a broadband emission spectrum of condensed phase samples covering the whole 5.

Mid-infrared, long wave infrared (4-12 μm) molecular emission signatures from pharmaceuticals using laser-induced breakdown spectroscopy (LIBS).

In an effort to augment the atomic emission spectra of conventional laser-induced breakdown spectroscopy (LIBS) and to provide an increase in selectivity, mid-wave to long-wave infrared (IR), LIBS studies were performed on several organic pharmaceuticals. Laser-induced breakdown spectroscopy signature molecular emissions of target organic compounds are observed for the first time in the IR fingerprint spectral region between 4-12 μm. The IR emission spectra of select organic pharmaceuticals closely correlate with their respective standard Fourier transform infrared spectra.

Long-wave, infrared laser-induced breakdown (LIBS) spectroscopy emissions from energetic materials.

Laser-induced breakdown spectroscopy (LIBS) has shown great promise for applications in chemical, biological, and explosives sensing and has significant potential for real-time standoff detection and analysis. In this study, LIBS emissions were obtained in the mid-infrared (MIR) and long-wave infrared (LWIR) spectral regions for potential applications in explosive material sensing. The IR spectroscopy region revealed vibrational and rotational signatures of functional groups in molecules and fragments thereof.

Mid-infrared emission from laser-induced breakdown spectroscopy.

Laser-induced breakdown spectroscopy (LIBS) is a powerful analytical technique for detecting and identifying trace elemental contaminants by monitoring the visible atomic emission from small plasmas. However, mid-infrared (MIR), generally referring to the wavelength range between 2.5 to 25 microm, molecular vibrational and rotational emissions generated by a sample during a LIBS event has not been reported.

Infrared to visible upconversion of Nd(3+) ions in KPb(2)Br(5) low phonon crystal.

In this work we present a detailed analysis of the infrared to visible upconversion in Nd(3+)-doped KPb(2)Br(5) low phonon crystal by using both steady-state and time-resolved luminescence spectroscopy. Efficient blue, green, orange, and red emissions have been observed under excitation into the (4)F(5/2) and (4)F(3/2) states. The low phonon energy of this crystal leads to a significant reduction of the multiphonon relaxation rates which allows most of the excited states to relax radiatively.