Detection of cracks and defects using electronic speckle pattern interferometry with a holographi... more Detection of cracks and defects using electronic speckle pattern interferometry with a holographic optical element. [Proceedings of SPIE 5226, 209 (2003)]. Emilia M. Mihaylova, Vincent Toal, Sridhar R. Guntaka, Suzanne Martin. Abstract. ...
Holographically recorded diffractive optical elements are described, which can be used to impleme... more Holographically recorded diffractive optical elements are described, which can be used to implement very simple self-aligning electronic speckle pattern interferometers (ESPI) and holographic interferometers requiring only a laser source and a CCD camera in the optical set-up. The ESPI systems can utilize transmission or reflection holographic optical elements (HOEs). The HOEs are essentially amplitude beamsplitters and recombiners whose recording and
Abstract—We describe an implementation of a laser Doppler vibrometer system. Two main subsystems ... more Abstract—We describe an implementation of a laser Doppler vibrometer system. Two main subsystems work in tandem to produce a novel and effective sensing combination. In the first subsystem, responsible for signal generation, many of the complex optical components commonly ...
Recent work on an acrylamide-based photopolymer holographic recording medium is presented. The li... more Recent work on an acrylamide-based photopolymer holographic recording medium is presented. The lifetime of recorded gratings is improved by the addition of cross-linking monomers. Shelf life is also improved. The effects of various constituents of the ...
Journal of Optics A: Pure and Applied Optics, 2005
... Least squares algorithm for rapid analysis of Fabry–Perot fringe patterns Michael O'... more ... Least squares algorithm for rapid analysis of Fabry–Perot fringe patterns Michael O'Hora, Brian Bowe and Vincent Toal Centre for Industrial and Engineering Optics, Dublin Institute of Technology,Kevin Street, Dublin 8, Republic of Ireland E-mail: michael.ohora@dit.ie ...
Frequency changes induced by bias or temperature modulation of injection diode lasers can provide... more Frequency changes induced by bias or temperature modulation of injection diode lasers can provide an economical and effective method of applying phase-stepping interferometry to optical metrology. However, the intrinsic frequency instability of these devices limits their use in gauge block interferometry where precise and repeatable phase steps must be maintained simultaneously on two discontinuous surfaces and over relatively long path lengths. We demonstrate a method using a visible injection diode laser, the frequency of which is locked by using a Fabry-Perot interferometer. Small changes to the length of the Fabry-Perot interferometer shift the frequency of the laser producing proportional and repeatable phase steps to the gauge block interferogram. This method has been successfully implemented with a Fizeau-type gauge block interferometer with a phase measurement resolution of 0.005 lambda. The phase data are then processed to map the surface form of gauge blocks up to 100 mm in length and to objectively assess surface shape parameters.
Detection of cracks and defects using electronic speckle pattern interferometry with a holographi... more Detection of cracks and defects using electronic speckle pattern interferometry with a holographic optical element. [Proceedings of SPIE 5226, 209 (2003)]. Emilia M. Mihaylova, Vincent Toal, Sridhar R. Guntaka, Suzanne Martin. Abstract. ...
Holographically recorded diffractive optical elements are described, which can be used to impleme... more Holographically recorded diffractive optical elements are described, which can be used to implement very simple self-aligning electronic speckle pattern interferometers (ESPI) and holographic interferometers requiring only a laser source and a CCD camera in the optical set-up. The ESPI systems can utilize transmission or reflection holographic optical elements (HOEs). The HOEs are essentially amplitude beamsplitters and recombiners whose recording and
Abstract—We describe an implementation of a laser Doppler vibrometer system. Two main subsystems ... more Abstract—We describe an implementation of a laser Doppler vibrometer system. Two main subsystems work in tandem to produce a novel and effective sensing combination. In the first subsystem, responsible for signal generation, many of the complex optical components commonly ...
Recent work on an acrylamide-based photopolymer holographic recording medium is presented. The li... more Recent work on an acrylamide-based photopolymer holographic recording medium is presented. The lifetime of recorded gratings is improved by the addition of cross-linking monomers. Shelf life is also improved. The effects of various constituents of the ...
Journal of Optics A: Pure and Applied Optics, 2005
... Least squares algorithm for rapid analysis of Fabry–Perot fringe patterns Michael O'... more ... Least squares algorithm for rapid analysis of Fabry–Perot fringe patterns Michael O'Hora, Brian Bowe and Vincent Toal Centre for Industrial and Engineering Optics, Dublin Institute of Technology,Kevin Street, Dublin 8, Republic of Ireland E-mail: michael.ohora@dit.ie ...
Frequency changes induced by bias or temperature modulation of injection diode lasers can provide... more Frequency changes induced by bias or temperature modulation of injection diode lasers can provide an economical and effective method of applying phase-stepping interferometry to optical metrology. However, the intrinsic frequency instability of these devices limits their use in gauge block interferometry where precise and repeatable phase steps must be maintained simultaneously on two discontinuous surfaces and over relatively long path lengths. We demonstrate a method using a visible injection diode laser, the frequency of which is locked by using a Fabry-Perot interferometer. Small changes to the length of the Fabry-Perot interferometer shift the frequency of the laser producing proportional and repeatable phase steps to the gauge block interferogram. This method has been successfully implemented with a Fizeau-type gauge block interferometer with a phase measurement resolution of 0.005 lambda. The phase data are then processed to map the surface form of gauge blocks up to 100 mm in length and to objectively assess surface shape parameters.
Uploads