Ilya Golub - Academia.edu (original) (raw)

Papers by Ilya Golub

Methods of Laser Spectroscopy, 1986

When an intense laser beam is blue detuned with respect to the D2 transition of sodium, at sodium... more When an intense laser beam is blue detuned with respect to the D2 transition of sodium, at sodium densities > 1013 cm−3 self-focusing occurs. At still higher densities and for laser detuning in the range 6–15 cm−1 to the blue side of the D2 line a coherent emission in the forward direction is observed.1 This emission is shifted 1–3 cm−1 to the blue of the D1 transition, depending on the sodium density, and, within the instrumental resolution of our spectrometer of 1.2 cm−1, its frequency is independent on the laser detuning. This emission was observed earlier both in potasium2 and sodium3 vapors, but was not studied thoroughly, neither was a satisfactory explanation presented. We present experimental data of this emission and show that non of the ordinary mechanisms, such as collision induced population transfer, three-photon effect etc., is consistent with the experimental results. We propose a laser photon splitting by the doublet system of sodium as a possible explanation of the “blue peak” emission.

Laser Spectroscopy, 1989

Publisher Summary Intense picosecond pulses propagating in nonlinear media can produce frequency ... more Publisher Summary Intense picosecond pulses propagating in nonlinear media can produce frequency broadened output beams with a nearly white spectrum called supercontinuum (SC). SC generation is correlated with self-focusing (SF) and self-trapped filament formation. This chapter discusses the effect in solids, liquids, and gases. Supercontinuum cone emission (SCCE) has the same circular or linear polarisation as that of the input laser beam. Any light of circular polarisation contains a small portion of counter rotating polarisation radiation. The weaker polarisation should be self-trapped before the stronger one, resulting in light changing its polarisation into a linear. That change occurs inside the filaments where the saturation degree is maximal. The SCCE angle is independent on the lens focal length in the range 5–20 cm. The SCCE, similar to conical emission in alkali metal vapors and class II radiation, is a radiation formed on the surface of the self-trapped filaments—a proce...

Intense radiation interacting with nonlinear media can generate a white spectrum emission called ... more Intense radiation interacting with nonlinear media can generate a white spectrum emission called supercontinuum (SC)1 accompanied by ring emission. Proposed models—self-phase modulation, four-wave mixing, and the Raman effect-fail to explain the effect even qualitatively. We present new results on properties of SC cone emission (SCCE) and discuss its similarity to conical emission in metal vapors2 and class II Raman emission in liquids.3

IEEE Journal of Quantum Electronics, 1992

A simple model system comprised of a thin nonlinear layer sandwiched between two glass plates is ... more A simple model system comprised of a thin nonlinear layer sandwiched between two glass plates is demonstrated. This nonlinear sandwich allows the investigation of both the transmitted and reflected beams for all-optical switching. With a thermal (negative) nonlinearity high-contrast switching is obtained within several nanoseconds. The authors also show for the first time, the avoidance of multiple thresholds and associated

O-Ion Implantation for Practical InP-Based Digital Optical Switches. [ASME Conference Proceedings... more O-Ion Implantation for Practical InP-Based Digital Optical Switches. [ASME Conference Proceedings 2003, 651 (2003)]. Pedro Barrios, Siegfried Janz, Ilya Golub, Philip Poole, Phillip Chow-Chong, Daniel Poitras, Irwin Sproule, Mark Malloy, André Delâge, Ross McKinnon, Barry Syrett, Shawky El-Mougy, Shawkat Abdalla. Abstract. The fabrication of Digital Optical Switches with O-ion implanted - electrical isolated - branches is described. Multiplevs. ...

Four-wave mixing in the vicinity of a sodium doublet is reported. The three-level system allows c... more Four-wave mixing in the vicinity of a sodium doublet is reported. The three-level system allows collinear phase-matching. The FWM is resonantly enhanced by a high gain on the blue side of the D1 transition.

Optical and quantum electronics, 2005

... K1A 0R6 2Steacie Institute for Molecular Sciences, NRC, 100 Sussex Drive, Ottawa ON, Canada (... more ... K1A 0R6 2Steacie Institute for Molecular Sciences, NRC, 100 Sussex Drive, Ottawa ON, Canada (*author for correspondence: E-mail: Andre.Delage@nrc ... of a repetition of high and low refractive index layers similar to the reflecting layers of ARROW waveguides (Duguay et al. ...

Integrated Photonics Research, 2003

... S. Janz, P. Barrios, A. Delâge, I. Golub, JJ He, WR McKinnon, P. Poole Institute for Microstr... more ... S. Janz, P. Barrios, A. Delâge, I. Golub, JJ He, WR McKinnon, P. Poole Institute for Microstructural Sciences, National Research Council Canada, Building M23A ... 10-3 K-1 . Hence the inferred temperature rise in our structure is of the order of a few degrees Kelvin, consistent with ...

2019 Photonics North (PN)

We present an optimization study for the magic carpet parameters. Using simple models and scalar ... more We present an optimization study for the magic carpet parameters. Using simple models and scalar diffraction theory, we calculate the light sheet depth of field (DOF) and thickness for different mask dimensions. Experimental results confirm the numerical results. The results serve as a guideline for selection of the mask depending on the application.

Optics & Laser Technology, 1999

ABSTRACT

Journal of the Optical Society of America B, 1989

Using a propagation cell that discriminated against the buildup of stimulated Raman emission, we ... more Using a propagation cell that discriminated against the buildup of stimulated Raman emission, we succeeded in observing self-focusing in pressurized air without interference from any competing nonlinear process. Measurements were made for air pressures between 20 and 40 atm. The data yielded a nonlinear refractive index n2 = (2.9 + 0.3) X 10-16 esu per atmosphere of air at 300 K for a 308-nm laser beam.

Physical Review Letters, 1996

Control over the product branching ratio in the photodissociation of Na 2 into Na͑3s͒ 1 Na͑3p͒ an... more Control over the product branching ratio in the photodissociation of Na 2 into Na͑3s͒ 1 Na͑3p͒ and Na͑3s͒ 1 Na͑3d͒ is demonstrated using a two-photon incoherent interference control scenario. Ordinary pulsed nanosecond lasers are used and Na 2 is at thermal equilibrium in a heat pipe. Results show a depletion in the Na͑3d͒ product of at least 25% and a concomitant increase in the Na͑3p͒ yield as the relative frequency of the two lasers is scanned.

Springer Proceedings in Physics, 1987

Spatially modulated gain of a distributed feedback dye laser (DFDL) is used to construct a laser-... more Spatially modulated gain of a distributed feedback dye laser (DFDL) is used to construct a laser-controlled reflective device. The mirror-type device has the tunability and spectral selectivity of the DFDL. The reflection occurs during DFDL pulse duration.

Optical Amplifiers and Their Applications/Integrated Photonics Research, 2004

ABSTRACT A compact 1x2 InGaAsP/InP waveguide digital optical switch with electrically reconfigura... more ABSTRACT A compact 1x2 InGaAsP/InP waveguide digital optical switch with electrically reconfigurable output waveguide arms is demonstrated. The carrier injection device exhibits better than 20 dB isolation and 3 nanosecond time response.

An intense transversely symmetric laser beam impinging on a prism with a nonlinear material exhib... more An intense transversely symmetric laser beam impinging on a prism with a nonlinear material exhibits intensity-dependent deflection.1 Conversely, a light with spatially nonuniform intensity distribution over its cross section is subject to self-bending while propagating through a nonlinear media.2 The self-bending is in the direction in which the refraction is maximal, i.e., in the direction of maximal intensity in the media with a positive nonlinear refractive index n2.

Journal of the Optical Society of America B, 2019

We report on mutual transformation of spin and orbital angular momenta (SAM and OAM) of light upo... more We report on mutual transformation of spin and orbital angular momenta (SAM and OAM) of light upon tight focusing of circularly polarized vortex beams. In some regions of the focal spot, the OAM of light changes by a value ±2ℏ, while the circular polarization (CP) there reverses its rotation direction, resulting in adjacent rings (or core and adjacent ring) of opposite CP handedness. Moreover, the SAM has a transverse angular momentum (AM) component. We show that while the whole pattern rotates around the optical axis at the rate of the optical frequency divided by the value of total AM, the 3D SAM “balls” between adjacent rings (or between a ring and a core) spin in an opposite direction at the rate of the optical frequency, constituting an optical analog of a ball bearing. The applications include manipulation of particles, e.g., optical tweezers or spanners.

Journal of the Optical Society of America A, 2018

We investigate the focusing of Poisson-spectrum few cycle pulsed light beams for linear, circular... more We investigate the focusing of Poisson-spectrum few cycle pulsed light beams for linear, circular, azimuthal, and radial input polarizations with and without a first-order vortex. It is shown that, for all the considered cases, the focal spot is tighter when compared to long pulses due to the increased blue frequency content in the ultrashort pulses spectrum. More significantly, we show, for what we believe is the first time, that upon pulse shortening different focused beam vector components associated with different Bessel functions J 0 and J 1 undergo a change in the relative weight of their respective contribution to the focal spot size. This effect is caused by the different spectral dependencies of J 0 and J 1 near the focus. This newly discovered property of broadband ultrashort pulses could be exploited in light-matter interactions advantageously.

Journal of the Optical Society of America A, 2018

Light sheet illumination is the basis in developing light sheet microscopy (LSM), a technique wit... more Light sheet illumination is the basis in developing light sheet microscopy (LSM), a technique with significant advantages compared with other classical techniques. Most proposed optical systems to generate light sheets for LSM use many optical elements, which require extensive adjustments and are costly; moreover, they generate a nonuniform or semiuniform light sheet or have a short depth of field (DOF). A simple scheme using a pair of double slits and a cylindrical lens for generating a quasi-nondiffracting 2D light sheet was reported in Opt. Lett.40, 5121 (2015)OPLEDP0146-959210.1364/OL.40.005121. In the present investigation, we elaborate on the optimization of the mask used. As the separation between the two slits increases, the light sheet becomes thinner and the DOF smaller and vice versa. The slits' width does not affect the light sheet thickness, but it does affect the intensity of the side lobes. For convergence angles of the inner slits from 0.75° to 8°, an optimum ratio of the slits' separation/width of 2.182 is recommended. The obtained light sheet is quasi-diffraction-free, namely, while its DOF is comparable with that of a Gaussian beam, its diffraction broadening is substantially smaller. We also add to the previously developed configuration a Powell lens in order to expand the beam in the spanwise direction while keeping nearly constant intensity in this dimension. We perform scalar diffraction theory calculations and conduct measurements showing the nearly constant intensity in the significantly broadened span of the light sheet. Potential applications for the augmented width include imaging of certain large embryos, laser micromachining, and microparticle image velocimetry.

Optics Letters, 2017

We demonstrate a novel method to measure circular birefringence (CB) and linear birefringence (LB... more We demonstrate a novel method to measure circular birefringence (CB) and linear birefringence (LB) present simultaneously in the device under study. By using a π-shifted Sagnac interferometer, the scheme eliminates the dependence on incoming polarization and on the orientation angle of the linear birefringence. Moreover, due to different handedness symmetry/response of CB and LB to counter-propagating waves, the technique allows us to control the relative influence of the two birefringences leading to a requirement of only two measurements to determine both of them. Thus, comparing to Stokes polarimeters and other methods, our scheme has advantages when characterizing media containing both birefringences. Our findings are experimentally confirmed.

Methods of Laser Spectroscopy, 1986

When an intense laser beam is blue detuned with respect to the D2 transition of sodium, at sodium... more When an intense laser beam is blue detuned with respect to the D2 transition of sodium, at sodium densities > 1013 cm−3 self-focusing occurs. At still higher densities and for laser detuning in the range 6–15 cm−1 to the blue side of the D2 line a coherent emission in the forward direction is observed.1 This emission is shifted 1–3 cm−1 to the blue of the D1 transition, depending on the sodium density, and, within the instrumental resolution of our spectrometer of 1.2 cm−1, its frequency is independent on the laser detuning. This emission was observed earlier both in potasium2 and sodium3 vapors, but was not studied thoroughly, neither was a satisfactory explanation presented. We present experimental data of this emission and show that non of the ordinary mechanisms, such as collision induced population transfer, three-photon effect etc., is consistent with the experimental results. We propose a laser photon splitting by the doublet system of sodium as a possible explanation of the “blue peak” emission.

Laser Spectroscopy, 1989

Publisher Summary Intense picosecond pulses propagating in nonlinear media can produce frequency ... more Publisher Summary Intense picosecond pulses propagating in nonlinear media can produce frequency broadened output beams with a nearly white spectrum called supercontinuum (SC). SC generation is correlated with self-focusing (SF) and self-trapped filament formation. This chapter discusses the effect in solids, liquids, and gases. Supercontinuum cone emission (SCCE) has the same circular or linear polarisation as that of the input laser beam. Any light of circular polarisation contains a small portion of counter rotating polarisation radiation. The weaker polarisation should be self-trapped before the stronger one, resulting in light changing its polarisation into a linear. That change occurs inside the filaments where the saturation degree is maximal. The SCCE angle is independent on the lens focal length in the range 5–20 cm. The SCCE, similar to conical emission in alkali metal vapors and class II radiation, is a radiation formed on the surface of the self-trapped filaments—a proce...

Intense radiation interacting with nonlinear media can generate a white spectrum emission called ... more Intense radiation interacting with nonlinear media can generate a white spectrum emission called supercontinuum (SC)1 accompanied by ring emission. Proposed models—self-phase modulation, four-wave mixing, and the Raman effect-fail to explain the effect even qualitatively. We present new results on properties of SC cone emission (SCCE) and discuss its similarity to conical emission in metal vapors2 and class II Raman emission in liquids.3

IEEE Journal of Quantum Electronics, 1992

A simple model system comprised of a thin nonlinear layer sandwiched between two glass plates is ... more A simple model system comprised of a thin nonlinear layer sandwiched between two glass plates is demonstrated. This nonlinear sandwich allows the investigation of both the transmitted and reflected beams for all-optical switching. With a thermal (negative) nonlinearity high-contrast switching is obtained within several nanoseconds. The authors also show for the first time, the avoidance of multiple thresholds and associated

O-Ion Implantation for Practical InP-Based Digital Optical Switches. [ASME Conference Proceedings... more O-Ion Implantation for Practical InP-Based Digital Optical Switches. [ASME Conference Proceedings 2003, 651 (2003)]. Pedro Barrios, Siegfried Janz, Ilya Golub, Philip Poole, Phillip Chow-Chong, Daniel Poitras, Irwin Sproule, Mark Malloy, André Delâge, Ross McKinnon, Barry Syrett, Shawky El-Mougy, Shawkat Abdalla. Abstract. The fabrication of Digital Optical Switches with O-ion implanted - electrical isolated - branches is described. Multiplevs. ...

Four-wave mixing in the vicinity of a sodium doublet is reported. The three-level system allows c... more Four-wave mixing in the vicinity of a sodium doublet is reported. The three-level system allows collinear phase-matching. The FWM is resonantly enhanced by a high gain on the blue side of the D1 transition.

Optical and quantum electronics, 2005

... K1A 0R6 2Steacie Institute for Molecular Sciences, NRC, 100 Sussex Drive, Ottawa ON, Canada (... more ... K1A 0R6 2Steacie Institute for Molecular Sciences, NRC, 100 Sussex Drive, Ottawa ON, Canada (*author for correspondence: E-mail: Andre.Delage@nrc ... of a repetition of high and low refractive index layers similar to the reflecting layers of ARROW waveguides (Duguay et al. ...

Integrated Photonics Research, 2003

... S. Janz, P. Barrios, A. Delâge, I. Golub, JJ He, WR McKinnon, P. Poole Institute for Microstr... more ... S. Janz, P. Barrios, A. Delâge, I. Golub, JJ He, WR McKinnon, P. Poole Institute for Microstructural Sciences, National Research Council Canada, Building M23A ... 10-3 K-1 . Hence the inferred temperature rise in our structure is of the order of a few degrees Kelvin, consistent with ...

2019 Photonics North (PN)

We present an optimization study for the magic carpet parameters. Using simple models and scalar ... more We present an optimization study for the magic carpet parameters. Using simple models and scalar diffraction theory, we calculate the light sheet depth of field (DOF) and thickness for different mask dimensions. Experimental results confirm the numerical results. The results serve as a guideline for selection of the mask depending on the application.

Optics & Laser Technology, 1999

ABSTRACT

Journal of the Optical Society of America B, 1989

Using a propagation cell that discriminated against the buildup of stimulated Raman emission, we ... more Using a propagation cell that discriminated against the buildup of stimulated Raman emission, we succeeded in observing self-focusing in pressurized air without interference from any competing nonlinear process. Measurements were made for air pressures between 20 and 40 atm. The data yielded a nonlinear refractive index n2 = (2.9 + 0.3) X 10-16 esu per atmosphere of air at 300 K for a 308-nm laser beam.

Physical Review Letters, 1996

Control over the product branching ratio in the photodissociation of Na 2 into Na͑3s͒ 1 Na͑3p͒ an... more Control over the product branching ratio in the photodissociation of Na 2 into Na͑3s͒ 1 Na͑3p͒ and Na͑3s͒ 1 Na͑3d͒ is demonstrated using a two-photon incoherent interference control scenario. Ordinary pulsed nanosecond lasers are used and Na 2 is at thermal equilibrium in a heat pipe. Results show a depletion in the Na͑3d͒ product of at least 25% and a concomitant increase in the Na͑3p͒ yield as the relative frequency of the two lasers is scanned.

Springer Proceedings in Physics, 1987

Spatially modulated gain of a distributed feedback dye laser (DFDL) is used to construct a laser-... more Spatially modulated gain of a distributed feedback dye laser (DFDL) is used to construct a laser-controlled reflective device. The mirror-type device has the tunability and spectral selectivity of the DFDL. The reflection occurs during DFDL pulse duration.

Optical Amplifiers and Their Applications/Integrated Photonics Research, 2004

ABSTRACT A compact 1x2 InGaAsP/InP waveguide digital optical switch with electrically reconfigura... more ABSTRACT A compact 1x2 InGaAsP/InP waveguide digital optical switch with electrically reconfigurable output waveguide arms is demonstrated. The carrier injection device exhibits better than 20 dB isolation and 3 nanosecond time response.

An intense transversely symmetric laser beam impinging on a prism with a nonlinear material exhib... more An intense transversely symmetric laser beam impinging on a prism with a nonlinear material exhibits intensity-dependent deflection.1 Conversely, a light with spatially nonuniform intensity distribution over its cross section is subject to self-bending while propagating through a nonlinear media.2 The self-bending is in the direction in which the refraction is maximal, i.e., in the direction of maximal intensity in the media with a positive nonlinear refractive index n2.

Journal of the Optical Society of America B, 2019

We report on mutual transformation of spin and orbital angular momenta (SAM and OAM) of light upo... more We report on mutual transformation of spin and orbital angular momenta (SAM and OAM) of light upon tight focusing of circularly polarized vortex beams. In some regions of the focal spot, the OAM of light changes by a value ±2ℏ, while the circular polarization (CP) there reverses its rotation direction, resulting in adjacent rings (or core and adjacent ring) of opposite CP handedness. Moreover, the SAM has a transverse angular momentum (AM) component. We show that while the whole pattern rotates around the optical axis at the rate of the optical frequency divided by the value of total AM, the 3D SAM “balls” between adjacent rings (or between a ring and a core) spin in an opposite direction at the rate of the optical frequency, constituting an optical analog of a ball bearing. The applications include manipulation of particles, e.g., optical tweezers or spanners.

Journal of the Optical Society of America A, 2018

We investigate the focusing of Poisson-spectrum few cycle pulsed light beams for linear, circular... more We investigate the focusing of Poisson-spectrum few cycle pulsed light beams for linear, circular, azimuthal, and radial input polarizations with and without a first-order vortex. It is shown that, for all the considered cases, the focal spot is tighter when compared to long pulses due to the increased blue frequency content in the ultrashort pulses spectrum. More significantly, we show, for what we believe is the first time, that upon pulse shortening different focused beam vector components associated with different Bessel functions J 0 and J 1 undergo a change in the relative weight of their respective contribution to the focal spot size. This effect is caused by the different spectral dependencies of J 0 and J 1 near the focus. This newly discovered property of broadband ultrashort pulses could be exploited in light-matter interactions advantageously.

Journal of the Optical Society of America A, 2018

Light sheet illumination is the basis in developing light sheet microscopy (LSM), a technique wit... more Light sheet illumination is the basis in developing light sheet microscopy (LSM), a technique with significant advantages compared with other classical techniques. Most proposed optical systems to generate light sheets for LSM use many optical elements, which require extensive adjustments and are costly; moreover, they generate a nonuniform or semiuniform light sheet or have a short depth of field (DOF). A simple scheme using a pair of double slits and a cylindrical lens for generating a quasi-nondiffracting 2D light sheet was reported in Opt. Lett.40, 5121 (2015)OPLEDP0146-959210.1364/OL.40.005121. In the present investigation, we elaborate on the optimization of the mask used. As the separation between the two slits increases, the light sheet becomes thinner and the DOF smaller and vice versa. The slits' width does not affect the light sheet thickness, but it does affect the intensity of the side lobes. For convergence angles of the inner slits from 0.75° to 8°, an optimum ratio of the slits' separation/width of 2.182 is recommended. The obtained light sheet is quasi-diffraction-free, namely, while its DOF is comparable with that of a Gaussian beam, its diffraction broadening is substantially smaller. We also add to the previously developed configuration a Powell lens in order to expand the beam in the spanwise direction while keeping nearly constant intensity in this dimension. We perform scalar diffraction theory calculations and conduct measurements showing the nearly constant intensity in the significantly broadened span of the light sheet. Potential applications for the augmented width include imaging of certain large embryos, laser micromachining, and microparticle image velocimetry.

Optics Letters, 2017

We demonstrate a novel method to measure circular birefringence (CB) and linear birefringence (LB... more We demonstrate a novel method to measure circular birefringence (CB) and linear birefringence (LB) present simultaneously in the device under study. By using a π-shifted Sagnac interferometer, the scheme eliminates the dependence on incoming polarization and on the orientation angle of the linear birefringence. Moreover, due to different handedness symmetry/response of CB and LB to counter-propagating waves, the technique allows us to control the relative influence of the two birefringences leading to a requirement of only two measurements to determine both of them. Thus, comparing to Stokes polarimeters and other methods, our scheme has advantages when characterizing media containing both birefringences. Our findings are experimentally confirmed.