Detection of doxorubicin-induced apoptosis of leukemic T-lymphocytes by laser tweezers Raman spectroscopy

Laser tweezers Raman spectroscopy (LTRS) was used to acquire the Raman spectra of leukemic T lymphocytes exposed to the chemotherapy drug doxorubicin at different time points over 72 hours. Changes observed in the Raman spectra were dependent on drug exposure time and concentration. The sequence of spectral changes includes an intensity increase in lipid Raman peaks, followed by an intensity increase in DNA Raman peaks, and finally changes in DNA and protein (phenylalanine) Raman vibrations. These Raman signatures are consistent with vesicle formation, cell membrane blebbing, chromatin condensation, and the cytoplasm of dead cells during the different stages of drug-induced apoptosis. These results suggest the potential of LTRS as a real-time single cell tool for monitoring apoptosis, evaluating the efficacy of chemotherapeutic treatments, or pharmaceutical testing

Effects of Rare-Earth Doping on Femtosecond Laser Waveguide Writing in Zinc Polyphosphate Glass

We have investigated waveguide writing in Er-Yb doped zinc polyphosphate glass using a femtosecond laser with a repetition rate of 1 KHz. We find that fabrication of good waveguides requires a glass composition with an O/P ratio of 3.25. The dependence on laser writing parameters including laser fluence, focusing conditions, and scan speed is reported. Waveguide properties together with absorption and emission data indicate that these glasses can be used for the fabrication of compact, high gain amplifying devices

Raman Spectroscopy of Single Crystals of High- Tc, Cuprates

We present normal mode assignments for the Raman spectra of 1-2-3-type materials on the basis of polarized Raman studies of single crystals of Ba2YCu3O7, Ba2YCu3O6, Sr2YCu2.4A10.607, and Ba2_xLaj+xCu3O7+δ. In Ba2YCu3O7 we observe five intrinsic modes at 500 [0(1) axial stretch], 435 [in-phase 0(2), 0(3) bend], 335 [out-of-phase 0(2), 0(3) bend], 140 [Cu(2) axial stretch mode], and 118 cm− 1(Ba axial mode). Defect-induced modes are found at 600 and 220 − 1. A mode at 640 − 1, which is seen only in ceramics, is shown to be due to a BaCuO2 impurity phase. Furthermore, we discuss the Raman spectra of Bi2Sr2Can − 1CunO4+2n, and the high-frequency (ω \u3e 1000 − 1) scattering in Ba2YCu3O6 and Ba2YCu3O7

Single-pass Waveguide Amplifiers in Er-Yb Doped Zinc Polyphosphate Glass Fabricated with Femtosecond Laser Pulses

We have investigated the direct fabrication of subsurface waveguide amplifiers in Er-Yb zinc polyphosphate glass by utilizing the relationship between the initial glass composition and the resulting changes to the network structure after modification by fs laser pulses. Waveguides, exhibiting internal gain of 1 dB/cm at 1.53 μm when pumped with 500 mW at 976 nm, were directly fabricated using a regenerative amplified Ti:sapphire 1 kHz, 180 fs laser system. Optical properties as well as insertion losses and internal gain are reported. © 2012 Optical Society of America

Influence of plasma-induced self-effects on surface ablation of glass using fs-laser pulses

San Francisco, California, USA, 13-18 February 2016Peer Reviewe

All-Optical Characterization of Fs-Laser Induced Refractive Index Changes in Bulk and At the Surface of Zinc Phosphate Glasses

The permanent refractive index change induced by ultrashort laser pulses in zinc phosphate glasses has been investigated both at the surface and in bulk. At the sample surface, irradiations have been performed by using loosely focused single fs-laser pulses at different energies. Optical microscopy images of the irradiations illustrate an interferometric pattern in form of concentric Newton rings due to the laser induced multilayer system (unmodified glass, thin laser-modified layer, air). This experimental reflectivity modulation along with simulations based on Abeles theory for multilayer optical systems allows retrieving laser-induced refractive index changes on the order of Δns= -10-3. In bulk, fs-laser written waveguides have been generated by translating the sample with respect to a tightly focused laser beam. The so-produced waveguides have been characterized by studying the optical near field of the TEM00 guided mode at 660 nm and using white light microscopy. The optical changes linked to the inscribed waveguides have been characterized by measuring the far field output profiles yielding values of approximately Δnb= +3·10-4. The laser-modified optical properties in bulk and at the surface will be linked to the glass structural changes as well as discussed in terms of the role of the incubation effects for multi-pulse processing

Evaluation of Escherichia coli Cell Response to Antibiotic Treatment by Use of Raman Spectroscopy with Laser Tweezers▿

Laser tweezers Raman spectroscopy was used to detect the cellular response of Escherichia coli cells to penicillin G-streptomycin and cefazolin. Time-dependent intensity changes of several Raman peaks at 729, 1,245, and 1,660 cm−1 enabled untreated cells and cells treated with the different antibiotic drugs to be distinguished