Slitless Optical-Fiber Laser-Raman Spectrometer Employing a Concave Holographic Grating

1977 ◽  
Vol 31 (4) ◽  
pp. 295-298 ◽  
Author(s):  
George E. Walrafen
Keyword(s):  
Optical Fiber ◽  
Fiber Laser ◽  
Numerical Aperture ◽  
Fused Silica ◽  
Holographic Grating ◽  
Photomultiplier Tube ◽  
Solid Core ◽  
Raman Spectrometer ◽  
Focal Line ◽  
Laser Raman

A slitless optical-fiber laser-Raman spectrometer has been developed that employs a single f/3 concave holographic diffraction grating. The exit end of an optical fiber is positioned at the grating focus, and the divergent excitation and Raman radiation are then dispersed and refocussed. Detection is accomplished by translating an exit slit and photomultiplier tube along the focal line. A moveable solid-core optical fiber that transmits light to a fixed photomultiplier tube may also be used. The holographic grating produces a straight focal line, instead of a curve, resulting in accurate focussing from 480 to 650 nm, with linear scanning. The low f-number grating was used to accommodate high numerical aperture optical fibers without loss of light. A comparison between the present spectrometer with a 55 m fused silica fiber and a Jarrell-Ash Czerny-Turner single monochromator using a 1-cm bulk sample indicates a signal/noise improvement by a factor of 137 for the very weak two-phonon band from fused silica near 1600 cm−1.

New Slitless Optical Fiber Laser-Raman Spectrometer

1975 ◽  
Vol 29 (2) ◽  
pp. 179-185 ◽  
Author(s):  
G. E. Walrafen
Keyword(s):  
Optical Fiber ◽  
Fiber Laser ◽  
Focal Plane ◽  
Fused Silica ◽  
Small Sample ◽  
Solid Core ◽  
Raman Spectrometer ◽  
Laser Raman ◽  
Wide Range ◽  
Doped Glasses

A new slitless optical fiber laser-Raman spectrometer has been developed in which long, thin, low loss optical fibers, either liquid filled or solid core, act simultaneously as the sample and entrance aperature. The fiber end is placed at the focus of the collimator lens, and the resultant parallel radiation is dispersed by three large triangular Steinheil prisms in series. The dispersed radiation is then focussed by the camera lens to a series of points in the focal plane. The Raman points are detected photoelectrically by scanning with either an exit pinhole or slit, and a photomultiplier whose photocathode surface can be as small as the fiber end. Because of the long fiber lengths employed and of the high transmission efficiency of the spectrometer, very large Raman signals result. For example, the extremely weak Raman intensity maximum from fused silica at Δ v̄bar; ≈ 2165 cm−1 is readily detected visually in the focal plane using a fiber length of 85 m and a few hundred milliwatts of 476.5 nm excitation. The new spectrometer will be of considerable use in Raman studies of pure and doped glasses in fiber form, and of a wide range of liquids and mixtures where small sample amounts are involved. It may also be possible eventually to extend this slitless method to studies of water, aqueous solutions, and gases by employing straight dielectric waveguide techniques.

scholarly journals Manifestation of propagation traits for polymer square lattice micro-structured optical fiber in THz regime: a simplified model

2021 ◽  
Author(s):  
Hukam Singh ◽  
Dinesh Kumar Sharma ◽  
Saurabh Mani Tripathi
Keyword(s):  
Optical Fiber ◽  
Numerical Aperture ◽  
Relative Sensitivity ◽  
Sensitivity Coefficient ◽  
Spot Size ◽  
Square Lattice ◽  
Confinement Loss ◽  
Design Parameters ◽  
Solid Core ◽  
Material Loss

Abstract To sustain the pace with immense prominence, interest in low-loss terahertz (THz) waveguides increases due to their particular applications in the multidisciplinary arena. This paper narrates a novel solid-core polymer-based square lattice micro-structured optical fiber (SL-MOF) with circular air-holes for efficient propagation of THz waves. The anticipated model’s guiding attributes are described by employing the numerically efficient finite-element method (FEM) in conjunction with an auxiliary Ring Model. Numerical analysis of the model exhibits confinement loss of about ~ 10 -7 dB/cm and low effective material loss of ~ 0.19 cm -1 at the applied frequency of 1.0 THz. It is also demonstrated that the considered geometry furnishes low bending loss over the extended range of THz frequency. The relative sensitivity coefficient is evaluated in context for the targeted design parameters to enable the said model’s practical utility. Other nameworthy propagation characteristics, such as effective mode-index, power fraction, effective mode-area, numerical aperture, spot-size, and the beam divergence are also investigated. The improved outcomes are anticipated that the proposed configuration will be opened a new epoch in the THz waveband.

Self-compression to 24 MW peak power in a fused silica solid-core fiber using a high-repetition rate thulium-based fiber laser system

2016 ◽  
Author(s):  
Martin Gebhardt ◽  
Christian Gaida ◽  
Fabian Stutzki ◽  
Steffen Hädrich ◽  
Cesar Jauregui ◽  
...  
Keyword(s):  
Fiber Laser ◽  
Repetition Rate ◽  
Peak Power ◽  
Laser System ◽  
High Repetition Rate ◽  
Fused Silica ◽  
Solid Core ◽  
High Repetition ◽  
Core Fiber

Generation of highly chirped pulses in a diode-pumped optical fiber laser

1997 ◽  
Vol 140 (1-3) ◽  
pp. 19-22 ◽  
Author(s):  
M. Baldo ◽  
G.E. Town ◽  
M. Romagnoli
Keyword(s):  
Optical Fiber ◽  
Fiber Laser ◽  
Chirped Pulses ◽  
Diode Pumped

Fabrication of Lensed Plastic Optical Fiber Array Using Electrostatic Force

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Yih-Tun Tseng ◽  
Jhong-Bin Huang ◽  
Che-Hsin Lin ◽  
Chin-Lung Chen ◽  
Wood-Hi Cheng
Keyword(s):  
Optical Fiber ◽  
Optical Fibers ◽  
Electrostatic Force ◽  
Coupling Efficiency ◽  
Numerical Aperture ◽  
Uv Curing ◽  
Power Budget ◽  
Fiber Array ◽  
Plastic Optical Fibers ◽  
Efficient Coupling

The GI (graded-index) POFs (Plastic optical fibers), which has been proven to reach distances as long as 1 km at 1.25 Gb/s has a relatively low numerical aperture . Therefore, the efficient coupling of GI POFs to the light source has become critical to the power budget in the system. Efficient coupling for a POFs system normally involves either a separate lens or the direct formation of the lens at the end of the fiber. Forming the lens-like structure directly on the fiber end is preferred for simplicity of fabrication and packaging, such as polishing and fusion, combine different fibers with the cascaded fiber method and hydroflouride (HF) chemical etching. These approaches are well established, but applicable only to glass. Optical assembly architecture for multichannel fibers and optical devices is critical to optical fiber interconnections. Multichannel fiber-pigtail laser diode (LD) modules have potential for supporting higher data throughput and longer transmission distances. However, to be of practical use, these modules must be more precise. This work proposes and manufactures lensed plastic optical fibers (LPOF) array. This novel manipulation can be utilized to fabricate an aspherical lens on a fiber array after the UV curing of the photo-sensitive polymer; the coupling efficiency (CE) is increased and exceeds 47% between the LD array and the fiber array.

A Miniaturized, 1.9F Integrated Optical Fiber and Stone Basket for Use in Thulium Fiber Laser Lithotripsy

2015 ◽  
Vol 29 (10) ◽  
pp. 1110-1114 ◽  
Author(s):  
Christopher R. Wilson ◽  
Thomas C. Hutchens ◽  
Luke A. Hardy ◽  
Pierce B. Irby ◽  
Nathaniel M. Fried
Keyword(s):  
Optical Fiber ◽  
Fiber Laser ◽  
Laser Lithotripsy ◽  
Integrated Optical ◽  
Thulium Fiber Laser

Optical-fiber laser Doppler velocimeter for high-resolution measurement of pulsatile blood flows

1982 ◽  
Vol 21 (10) ◽  
pp. 1785 ◽  
Author(s):  
H. Nishihara ◽  
J. Koyama ◽  
N. Hoki ◽  
F. Kajiya ◽  
M. Hironaga ◽  
...  
Keyword(s):  
High Resolution ◽  
Optical Fiber ◽  
Fiber Laser ◽  
Laser Doppler ◽  
Laser Doppler Velocimeter ◽  
Blood Flows ◽  
High Resolution Measurement ◽  
Resolution Measurement

scholarly journals Etching Process Related Changes and Effects on Solid-Core Single-Mode Polymer Optical Fiber Grating

2016 ◽  
Vol 8 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Kishore Bhowmik ◽  
Gang-Ding Peng ◽  
Yanhua Luo ◽  
Eliathamby Ambikairajah ◽  
Vedran Lovric ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Single Mode ◽  
Etching Process ◽  
Fiber Grating ◽  
Solid Core ◽  
Polymer Optical Fiber

Development of an Optical Fiber Sensor with a D-shaped Fiber Bragg Grating Integrated in a Loop-mirror Optical Fiber Laser as a High Sensitivity Refractometer

2021 ◽  
Vol 32 ◽  
Author(s):  
Binh Pham Thanh ◽  
Thuy Van Nguyen ◽  
Van Hoi Pham ◽  
Huy Bui ◽  
Thi Hong Cam Hoang ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Fiber ◽  
Fiber Laser ◽  
Fiber Bragg Grating ◽  
Limit Of Detection ◽  
Optical Fiber Sensor ◽  
High Sensitivity ◽  
Optical Signal ◽  
Bragg Grating ◽  
Loop Mirror

In this paper, we report a new type of refractometer based on a D-shaped fiber Bragg grating (FBG) integrated in a loop-mirror optical fiber laser. This proposed sensor is used in wavelength interrogation method, in which the D-shaped FBG is applied as a refractive index (RI) sensing probe and a mirror to select mode of laser. The D-shaped FBG is prepared by the removal of a portion of the fiber cladding covering the FBG by means of side-polishing technique. The D-shaped FBG sensing probe integrated in a loop-mirror optical fiber laser with saturated pump technique, the characteristics of sensing signals have been improved to obtain stable intensity, narrower bandwidth and higher optical signal-to-noise ratio compare to normal reflection configuration. The limit of detection (LOD) of this sensor can be achieved to 2.95 x 10-4 RIU in the refractive index (RI) range of 1.42-1.44. Accordingly, we believe that the proposed refractometer has a huge potential for applications in biochemical-sensing technique.

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