scholarly journals Construction and Operation of a dispersive Laser Raman Spectrograph using interference filter

1970 ◽  
Vol 32 (1) ◽  
pp. 121-129
Author(s):  
KM Abedin ◽  
SFU Farhad ◽  
MR Islam ◽  
Aminul I Talukder ◽  
AFMY Haider
Keyword(s):  
Raman Spectra ◽  
Notch Filter ◽  
Ccd Camera ◽  
Interference Filter ◽  
Spectral Lines ◽  
Quantitative Chemical Analysis ◽  
Laser Raman ◽  
Holographic Notch Filter ◽  
Cooled Ccd ◽  
Anti Stokes

A dispersive laser Raman system was designed and constructed using a helium-neon (He-Ne) laser as an excitation source, and an interference filter in the reflection mode for Raleigh filtering instead of the more common holographic notch filter. A commercially available spectrograph equipped with a cooled CCD camera was used to acquire the Raman spectra. The constructed laser Raman spectrograph was found to have excellent performance and sensitivity. Stokes Raman spectra of some common chemicals were acquired by the system, and the wavelengths of spectral lines agreed well with the literature values, within experimental error. The useful spectral range of the system is about 200-4000 cm-1. It was also possible to acquire anti-Stokes Raman spectra of one chemical (CCl4) without much difficulty. We hope to use the system for chemical identification of molecules as well as quantitative chemical analysis. To our knowledge, this is the first laser Raman system constructed in Bangladesh. doi: 10.3329/jbas.v32i1.2451 Journal of Bangladesh Academy of Sciences, Vol. 32, No. 1, 121-129, 2008

Performance of a Holographic Supernotch Filter

1993 ◽  
Vol 47 (3) ◽  
pp. 305-308 ◽  
Author(s):  
Christian L. Schoen ◽  
Shiv K. Sharma ◽  
Charles E. Helsley ◽  
Harry Owen
Keyword(s):  
Raman Spectroscopy ◽  
Raman Spectra ◽  
Comparative Evaluation ◽  
Low Frequency ◽  
Notch Filter ◽  
Rayleigh Line ◽  
Rejection Filter ◽  
Excitation Line ◽  
Holographic Notch Filter ◽  
Anti Stokes

Results are presented of a comparative evaluation of a holographic supernotch filter (HSNF) and a holographic notch filter (HNF) as a Rayleigh line rejection filter for Raman spectroscopy. The filter permits acquisition of both Stokes and anti-Stokes spectra down to ±200 cm−1 shift from excitation simultaneously, without filter angle adjustment. With slight angle adjustment, spectra can be recorded as close as 41 cm−1 from the excitation line. Performance of the HSNF is evaluated by measuring the low-frequency Raman spectra of Tb2(MoO4)3, water, and naphthalene.

Holographic Notch Filter for Low-Wavenumber Stokes and Anti-Stokes Raman Spectroscopy

1991 ◽  
Vol 45 (9) ◽  
pp. 1533-1536 ◽  
Author(s):  
Bijun Yang ◽  
Michael D. Morris ◽  
Harry Owen
Keyword(s):  
Raman Spectroscopy ◽  
Notch Filter ◽  
Holographic Notch Filter ◽  
Anti Stokes

scholarly journals Biocompatible Temperature Nanosensors Based on Titanium Dioxide

Proceedings ◽  
2020 ◽  
Vol 60 (1) ◽  
pp. 16
Author(s):  
Veronica Zani ◽  
Danilo Pedron ◽  
Roberto Pilot ◽  
Raffaella Signorini
Keyword(s):  
Titanium Dioxide ◽  
Spatial Resolution ◽  
Optical Sensors ◽  
Scattered Light ◽  
Ccd Camera ◽  
Contactless Measurement ◽  
Temperature Detection ◽  
Frequency Position ◽  
Cooled Ccd ◽  
Anti Stokes

The measurement of temperature is of fundamental importance in a huge scale of applications, from nanomedicine, where the early detection of tumorous cells is an essential requirement, to microelectronics and microcircuits. Optical sensors with a micro/nano-spatial resolution can be used for temperature determination within a biological frame. Within this context, Raman spectroscopy is particularly interesting: the inelastic scattering of light has the advantage of a contactless measurement and exploits the temperature-dependence of intensities in the spectrum by observing the intensity ratio of anti-Stokes and Stokes signals. Titanium dioxide can be regarded as a potential optical material for temperature detection in biological samples, thanks to its high biocompatibility, already demonstrated in literature, and to its strong Raman scattering signal. The aim of the present work is the realization of biocompatible optical thermometers, with a sub-micrometric spatial resolution, made of titanium dioxide. Raman measurements have been performed on anatase powder using 514.5, 568.2 and 647.1 nm excitation lines of the CW Ar/Kr ion laser. The laser beam was focalized through a microscope on the sample, kept at defined temperature using a temperature controller. The Stokes and anti-Stokes scattered light was analyzed through a triple monochromator and detected by a liquid nitrogen-cooled CCD camera. Raw data were analyzed with Matlab and Raman spectrum parameters—such as area, intensity, frequency position and width of the peak—were calculated using a Lorentz fitting curve. Preliminary results showed that good reliable temperatures can be obtained.

Five-Dimensional Microscopy using Widefield-Deconvolution: Practical Considerations and Biological Applications

1996 ◽  
Vol 54 ◽  
pp. 268-269
Author(s):  
W.F. Marshall ◽  
K. Oegema ◽  
J. Nunnari ◽  
A.F. Straight ◽  
D.A. Agard ◽  
...  
Keyword(s):  
Confocal Microscopy ◽  
High Speed ◽  
Laser Scanning ◽  
Ccd Camera ◽  
Image Plane ◽  
Time Lapse ◽  
Laser Scanning Confocal Microscopy ◽  
Three Dimensions ◽  
Excitation Light ◽  
Cooled Ccd

The ability to image cells in three dimensions has brought about a revolution in biological microscopy, enabling many questions to be asked which would be inaccessible without this capability. There are currently two major methods of three dimensional microscopy: laser-scanning confocal microscopy and widefield-deconvolution microscopy. The method of widefield-deconvolution uses a cooled CCD to acquire images from a standard widefield microscope, and then computationally removes out of focus blur. Using such a scheme, it is easy to acquire time-lapse 3D images of living cells without killing them, and to do so for multiple wavelengths (using computer-controlled filter wheels). Thus, it is now not only feasible, but routine, to perform five dimensional microscopy (three spatial dimensions, plus time, plus wavelength).Widefield-deconvolution has several advantages over confocal microscopy. The two main advantages are high speed of acquisition (because there is no scanning, a single optical section is acquired at a time by using a cooled CCD camera) and the use of low excitation light levels Excitation intensity can be much lower than in a confocal microscope for three reasons: 1) longer exposures can be taken since the entire 512x512 image plane is acquired in parallel, so that dwell time is not an issue, 2) the higher quantum efficiently of a CCD detect over those typically used in confocal microscopy (although this is expected to change due to advances in confocal detector technology), and 3) because no pinhole is used to reject light, a much larger fraction of the emitted light is collected. Thus we can typically acquire images with thousands of photons per pixel using a mercury lamp, instead of a laser, for illumination. The use of low excitation light is critical for living samples, and also reduces bleaching. The high speed of widefield microscopy is also essential for time-lapse 3D microscopy, since one must acquire images quickly enough to resolve interesting events.

Gamma-ray imaging with an image intensifier and a cooled CCD camera

2001 ◽  
Author(s):  
Naoki Saitoh ◽  
Kenro Kuroki ◽  
Kenji Kurosawa ◽  
Norimitsu Akiba
Keyword(s):  
Gamma Ray ◽  
Image Intensifier ◽  
Ccd Camera ◽  
Gamma Ray Imaging ◽  
Cooled Ccd

Dimethylnitrosamine Detection and Measurement Using Laser Raman Spectroscopy

1977 ◽  
Vol 31 (6) ◽  
pp. 515-518 ◽  
Author(s):  
Dwaine M. Thomas
Keyword(s):  
Raman Spectroscopy ◽  
Raman Spectra ◽  
Laser Raman Spectroscopy ◽  
Laser Raman ◽  
Signal Response

The Raman spectra of various concentrations of dimethylnitrosamine in water have been measured. The lowest concentration detected was 10 mg/l. Instrumental parameters were varied to optimize the signal response.

Rugged Fiber-Optic Raman Probe for Process Monitoring Applications

2001 ◽  
Vol 55 (10) ◽  
pp. 1337-1340 ◽  
Author(s):  
Pentti Niemelä ◽  
Janne Suhonen
Keyword(s):  
Fiber Optic ◽  
Signal To Noise Ratio ◽  
Notch Filter ◽  
Laser Line ◽  
Fiber Optic Probe ◽  
Monitoring Applications ◽  
Optic Probe ◽  
Holographic Notch Filter ◽  
Filter Thickness ◽  
Raman Probe

We report on the development of a simple, rugged fiber-optic probe for process Raman measurements, in which laser line rejection is based on an absorptive longpass filter made from a direct bandgap CdTe semiconductor. The probe can be used with a fixed wavelength laser at 830 nm, and Raman spectra can be recorded down to 200 cm−1 from the laser line. The filter thickness can be adjusted for final turning of the filter edge, as the edge slope is almost independent of thickness in the range 0.1 to 1 mm. Other properties of the probe, such as its signal-to-noise ratio and signal-to-background ratio, are shown to compare well with those of a state-of-the-art probe based on holographic notch filter techniques.

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