The paper reviews the past 11 years of literature on the application of diode lasers in atomic absorption spectrometry with graphite furnaces (GF), plasmas and flames as atomizers. Experimental arrangements and techniques for powerful absorption measurements as well as the theoretical background are covered. The analytical possibilities of high-resolution spectroscopy, including Dopplerfree techniques for isotope selective measurements and isotope dilution analysis are discussed and various applications of element-selective detection by diode laser atomic absorption in combination with separation techniques, such as liquid (LC) and gas chromatography (GC), and with laser ablation of solid samples, are presented.

Introduction: Regarding to the ground water pollution by Arsenic (As) in Ghorveh and Bijar field, contamination levels have been analyzed in irrigated plants (potato and carrot samples).Materials and Methods: Analyzes method have been by atomic absorption spectroscopy. Twenty four potato samples (of the 12 potato plots) and 4 carrot samples (of the 2 carrot plots) picked up and As contents were measured in skin and yield tissue separately. In potato of total 24 samples, 11 samples had less than 10 mg As/kg, 9 samples had to10- 20 and 4 samples had As in the range of 20- 25 mg As/kg. Skin-related Arsenic was higher than it in yield tissue. Of total skin samples: 17 samples had less than 50 mg As/kg, 5 samples had As in the range of 50 t0 100 and the last 2 samples had As in the range of 200-300 mg As/kg. All carrot samples showed As content less than 5 mg As/kg.Result and Discussion: (As) was high is some samples in skin of potato regarding to less transfer rate to eatable section, quantity will less with separate skin. In carrot, high quantity Arsenic ion is absorbed by roots because it has vast roots and transport in skin and.

. An annular cell with elliptical cross section and small physical size is introduced and simulated for increasing the absorption length in the spectroscopy. In this investigation by changing of the geometrical radius of the ellipse an absorption length of 15. 50 m is obtained. By the optimization of the cell and including the sagittal and tangential radius of the ellipse that reflect the beam, it is shown that at the obtained absorption length, it is possible to reduce the divergence of the beam down to 54 µ m. Then, signal-to-noise ratio (SNR) is calculated for R(16) CO2 absorption line by assuming that the cell is filled by the gas. The results of this calculation indicated that under optimum condition the SNR can be increased up to 310. Finally, the cell is optimized using Genetic algorithm by including all the effective parameters which affect the efficiency of the cell. We found that in the best case an absorption length of 8. 24 m with a SNR of 107 can be achieved when the geometrical radius of the cell being fixed at 5. 95 and 4. 59 cm.

In the present work, Se and Mn analysis was carried out among some popular Iranian herbal drops to monitor a possible accumulation of adverse elements. In this study, five different herbal drops present in Iranian market were selected, and 45 samples of each (totally 225 samples) were collected, and analyzed for the presence and determination of selenium and manganese using graphite furnace atomic absorption spectrometry. Samples were prepared by the dry ashing method at 450 °C, and the residue was dissolved in nitric acid. Se and Mn contents were determined using calibration curves at wavelength 196.0 and 279.5 nm respectively. LOD of the methods were determined as 9.1 µgL-1 for Se and 0.9 µgL-1 for Mn. LOQs were calculated to be 30.0 and 3.0 µgL-1 for Se and Mn, respectively. The Se concentrations in the determined samples were between ND-21.0 µgL-1 and for Mn were in the range of 7.2-1840.7 µgL-1. Mean Se and Mn concentrations (µgL-1) were 4.7 and 43.7 for Vitagnus, 9.6 and 185.1 for Hypiran, 13.3 and 338.5 for Carminat, 21.0 and 1840.7 for Persica, and ND and 7.2 for Menthol, respectively. The results showed that Mn was present in all of the samples analyzed, but no selenium was detected in some herbal drop samples.

Transient absorption spectroscopy allows the observation of excited state dynamics following optical excitation across a wide range of time scales, from femtoseconds to milliseconds. This article presents an ultrafast transient absorption spectroscopy setup based on the pump-probe method, utilizing femtosecond pulses from a Ti:sapphire laser at both fundamental and second harmonic wavelengths. We investigated the transient absorption spectrum of deionized water, the most common solvent, with femtosecond time resolution in two modes: one with a fixed delay time for probe wavelengths ranging from 740 to 820 nm, and the other with a fixed probe wavelength for various time delays up to 1.1 picoseconds. The transient absorption spectra reveal a negative signal peaking at 788 nm, attributed to ground state bleaching caused by the depopulation of the ground state induced by the pump. Additionally, a negative signal at 798 nm, resulting from stimulated emission, overlaps with a 10 nm Stokes shift of the ground state bleaching band. The temporal evolution of the transient absorbance spectra shows an absorption peak at a 70 femtosecond delay between the pump and probe pulses, indicating an unstable intermediate level resulting from a two-photon absorption process—one photon from the pump pulse at 392 nm and another from the probe pulse at 784 nm. Fitting a biexponential function to the relaxation data yields a lifetime of approximately 150 femtoseconds for this intermediate leve.

In this study, we present the design and fabrication of a V-shaped resonator that served as an absorption chamber in a laser spectroscopy system for water stable isotope measurement (2H, 17O, 18O) based on optical feedback cavity-enhanced absorption spectroscopy. In the design of a resonator, its length and the radius of curvature of the mirrors guarantee the optical stability of the system. The resonator mirrors are designed considering the condition of stability and based on the desired mode structure of the resonator output. The V-shaped resonator is designed with two arms of 40 cm and inner diameters of 5 mm making an angle of 1.7°. This resonator has an internal volume of 20 cm3 which provides fast response of laser spectrometer. The high reflectivity of mirrors leads to an effective absorption optical path length of 13 km and a high finesse optical resonator of   Ƒ~52،000. These values allow low concentration water vapor isotope analyses and resolution of the absorption spectrum of isotopes for accurate isotope measurements, respectively. Resonator mirrors are designed using Mcleod software to have maximum reflectance at a wavelength of 1.4 micrometers. By making a V-shaped optical resonator for measuring stable isotopes of water and subsequent development for measuring stable isotopes of other elements, the possibility of developing the application of stable isotopes in different areas of research will be provided.