Showing papers in "Optics Letters in 1986"
TL;DR: Optical trapping of dielectric particles by a single-beam gradient force trap was demonstrated for the first reported time, confirming the concept of negative light pressure due to the gradient force.
Abstract: Optical trapping of dielectric particles by a single-beam gradient force trap was demonstrated for the first reported time. This confirms the concept of negative light pressure due to the gradient force. Trapping was observed over the entire range of particle size from 10 μm to ~25 nm in water. Use of the new trap extends the size range of macroscopic particles accessible to optical trapping and manipulation well into the Rayleigh size regime. Application of this trapping principle to atom trapping is considered.
6,434 citations
TL;DR: The experimental discovery of a continuous shift in the optical frequency of a soliton pulse as it travels down the fiber is described, caused by a Raman self-pumping of the soliton.
Abstract: We describe the experimental discovery of a continuous shift in the optical frequency of a soliton pulse as it travels down the fiber. The effect is caused by a Raman self-pumping of the soliton, by which energy is transferred from the higher to the lower-frequency parts of its spectrum. For 120-fsec pulses, we have observed net frequency shifts as great as 10% of the optical frequency.
1,095 citations
TL;DR: The theory of Raman effects, which causes a continuous downshift of the mean frequency of pulses propagating in optical fibers, agrees well with recent measurements.
Abstract: Raman effects cause a continuous downshift of the mean frequency of pulses propagating in optical fibers. For solitons in silica fibers, the effect varies roughly with the inverse fourth power of the pulse width. At 1.5-μm wavelength in a fiber with 15 psec/nm/km time-of-flight dispersion, a soliton of 250-fsec duration is predicted to shift by its own spectral width after about 100m of propagation. The theory agrees well with recent measurements.
1,051 citations
TL;DR: It is shown that amplifier noise causes a soliton's group velocity to undergo a random-walk process, which limits the system's product of length times bit rate, in one example, to about 24 000 GHz-km.
Abstract: In an optical-communications system using soliton pulse transmission, periodic amplification is needed to maintain the energy of the solitons. We show that amplifier noise causes a soliton's group velocity to undergo a random-walk process. The resultant timing errors at the receiver limit the system's product of length times bit rate, in one example, to about 24 000 GHz-km.
845 citations
TL;DR: The frequency-doubled light generated in the glass fibers was sufficient to pump a commercial Rh6G dye laser with ~19% efficiency at 570 nm.
Abstract: Efficient frequency doubling of a cw Q-switched and mode-locked Nd:YAG laser has been observed in commercial single-mode optical glass fibers. Pulses of duration ~55 psec and intensities as high as ~0.55 kW were produced at 0.53 μm. The maximum peak power-conversion efficiency measured was ~3%. The frequency-doubled light generated in the glass fibers was sufficient to pump a commercial Rh6G dye laser with ~19% efficiency at 570 nm.
560 citations
TL;DR: Nonlinear pulse propagation is investigated in the neighborhood of the zero-dispersion wavelength in monomode fibers and it is found that the pulses break apart if lambda - lambda(0) is sufficiently small, owing to the third-order dispersion.
Abstract: Nonlinear pulse propagation is investigated in the neighborhood of the zero-dispersion wavelength in monomode fibers. When the amplitude is sufficiently large to generate breathers (N > 1 solitons), it is found that the pulses break apart if λ – λ0 is sufficiently small, owing to the third-order dispersion. Here λ0 denotes the zero-dispersion wavelength. By contrast, the solitary-wave (N = 1) solution appears well behaved for arbitrary λ – λ0. Implications for communication systems and pulse compression are discussed.
436 citations
TL;DR: An all-fiber-optic frequency shifter is demonstrated that uses mode coupling between the LP(01) and LP(11) modes by a traveling acoustic flexural wave guided along the optical fiber.
Abstract: An all-fiber-optic frequency shifter is demonstrated that uses mode coupling between the LP(01) and LP(11) modes by a traveling acoustic flexural wave guided along the optical fiber. The input and output leads of this frequency shifter are single-mode fibers. Unity mode-conversion efficiency for cw operation is achieved at 8-MHz frequency shift with about 0.25 W of electrical input power. Carrier and image sideband suppression of 15 and 35 dB, respectively, are demonstrated.
320 citations
TL;DR: An all-optical associative memory system that uses a holographic data base and phase-conjugate mirrors to provide optical feedback, thresholding, and gain is described.
Abstract: We describe an all-optical associative memory system that uses a holographic data base. Phase-conjugate mirrors are used to provide optical feedback, thresholding, and gain. Analysis and preliminary experiments are discussed.
250 citations
TL;DR: The first reported experimental observation of an extremely fast shift of the n = 1 exciton transition energy in GaAs quantum-well heterostructures is described and interpreted in terms of an optical Stark effect.
Abstract: We describe the first reported experimental observation of an extremely fast shift of the n = 1 exciton transition energy in GaAs quantum-well heterostructures. The shift is produced by optical pumping below the band gap and is not associated with a carrier or exciton population. We interpret the shift in terms of an optical Stark effect. We present a model for the Stark effect on the ground-state exciton in quantum wells and find good agreement between the predictions of the model and our experimental results.
244 citations
TL;DR: A band-conduction model for the photorefractive effect is derived in which simultaneous hole and electron conduction is taken into account and the anomalous behavior of nearly compensated BaTiO3 crystals in beam-coupling experiments is explained.
Abstract: A band-conduction model for the photorefractive effect is derived in which simultaneous hole and electron conduction is taken into account. The anomalous behavior of nearly compensated BaTiO3 crystals in beam-coupling experiments is explained.
237 citations
TL;DR: The data show that the currently unexplained macroscopic polar order of this classic representative of connective tissue is due both to a coherent network containing a large number of fine, polar, filamentlike structures that permeate the entire tendon volume and to a small number of intensely polar surface patches.
Abstract: We present the first reported optical second-harmonic microscope images of a biological sample—rattail tendon—and discuss, also for the first time, the need to distinguish between coherent and incoherent second-harmonic imaging. Our data show that the currently unexplained macroscopic polar order of this classic representative of connective tissue is due both to a coherent network containing a large number of fine, polar, filamentlike structures that permeate the entire tendon volume and to a small number of intensely polar surface patches.
TL;DR: Optical ranging using femtosecond laser pulses and nonlinear-optical cross correlation is demonstrated for the investigation of the microstructure of biological systems and the epidermal structure of human skin in vitro.
Abstract: Optical ranging using femtosecond laser pulses and nonlinear-optical cross correlation is demonstrated for the investigation of the microstructure of biological systems. By using pulses of 65-fsec duration generated by a colliding-pulse mode-locked ring dye laser, a spatial resolution of less than 15 μm is achieved with a detection sensitivity to remitted signals as small as 10−7 of the incident pulse energy. This technique is applied to measure the cornea in rabbit eyes in vivo as well as to investigate the epidermal structure of human skin in vitro.
TL;DR: Efficient and selective coupling between a single-mode fiber and the LP(11) mode of a double-mode Fiber is demonstrated in an evanescent directional coupler that has application as a modal filter for the construction of in-line all-fiber optical components.
Abstract: Efficient and selective coupling between a single-mode fiber and the LP11 mode of a double-mode fiber is demonstrated in an evanescent directional coupler. With greater than 90% coupling to the LP11 mode, suppression of the coupled power to the lower-order LP01 mode was measured to be at least 24 dB. This device has application as a modal filter for the construction of in-line all-fiber optical components.
TL;DR: A coherent optical memory that operates on the principle that an optical resonator employing a holographic grating can have user-prescribed eigenmodes and exhibiting associative recall is demonstrated.
Abstract: A coherent optical memory is described The device operates on the principle that an optical resonator employing a holographic grating can have user-prescribed eigenmodes Each information entity (eg, an image of a cat) defines an eigenmode of the resonator The stored information is accessed by injecting partial information (eg, an image of the cat’s ear) into the resonator A gain medium internal to the resonator amplifies the field belonging to the eigenmode that most resembles the injected field; the other eigenmodes are suppressed through a competition for the gain A simple optical memory exhibiting associative recall is demonstrated
TL;DR: An efficient LP01 to LP11 modal coupler using periodic microbends, spaced by a beat length between the modes, is built and tested and the optical-wavelength dependence is investigated, as are the polarization characteristics and the LP mode approximation.
Abstract: An efficient LP01 to LP11 modal coupler using periodic microbends, spaced by a beat length between the modes, was built and tested. The optical-wavelength dependence of the device is investigated, as are the polarization characteristics and the LP mode approximation. Finally, the loss of the modal coupler was measured as a function of wavelength.
TL;DR: The intensity-dependent refractive index leads to an instability in the polarization state of an intense light beam oriented along the fast axis of a birefringent nonlinear medium.
Abstract: The intensity-dependent refractive index leads to an instability in the polarization state of an intense light beam oriented along the fast axis of a birefringent nonlinear medium. Depending on initial conditions, the spatial evolution of the polarization state can be oscillatory or rotatory, in a manner analogous to the motion of a nonlinear pendulum.
TL;DR: The detection of OH in a laminar premixed air–methane flame by degenerate four-wave mixing (DFWM) is reported, showing clearly resolved rotational structure.
Abstract: The detection of OH in a laminar premixed air–methane flame by degenerate four-wave mixing (DFWM) is The detection reported. The four-wave mixing spectrum was recorded in the region of the R1, R2 band heads of the (0, 0) 2∑–2Π transition, showing clearly resolved rotational structure. Applications of the DFWM technique to combustion are discussed. As an example, the distribution of sodium atoms in a sodium-seeded flame has been diagnostics measured using a 90° geometry to enhance spatial resolution.
TL;DR: The Rhodamine/water solution provides a useful model system for studying the properties of oscillators based on whispering-gallery-wave spherical cavities and the low threshold for lasing, 10(4) W/cm(2) for 10(-4) M solutions, is consistent with particle size and cavity Q factor.
Abstract: We report lasing characteristics of 40-60-microm-diameter Rhodamine 590/water solution droplets pumped by a 20-nsec-duration Q-switched laser The Rhodamine/water solution provides a useful model system for studying the properties of oscillators based on whispering-gallery-wave spherical cavities The low threshold for lasing, 10(4) W/cm(2) for 10(-4) M solutions, is consistent with particle size and a cavity Q factor of 10(4) Portions of the droplet lase purely in transverse electric (TE) modes, while other portions contain both TE and lower-Q transverse magnetic modes In the far field, the lasing droplet approximates a coherent point source emitting in all directions
TL;DR: It is shown that, if the phase nonuniformity of the LCTV is corrected by a liquid gate, then a simple computer-generated hologram can be written and coherently reconstructed.
Abstract: A novel use of liquid-crystal television (LCTV) is described. It is shown that, if the phase nonuniformity of the LCTV is corrected by a liquid gate, then a simple computer-generated hologram can be written and coherently reconstructed.
TL;DR: An optical fiber whose structure is similar to that of the PANDA fiber, but with two open channels in the place of the stress members, is investigated.
Abstract: An optical fiber whose structure is similar to that of the PANDA fiber, but with two open channels in the place of the stress members, is investigated. Variations of the internal or external gas pressure permit tuning of the fiber birefringence (10−4 rad m−1 Pa−1) over a wide range, including sign reversal, and application as a pressure sensor.
TL;DR: A new technique for maintaining single-frequency output from injection-seeded Nd:YAG lasers is described, which involves quickly sweeping the slave-cavity longitudinal-mode spectrum when the flash lamps have created a maximum population inversion.
Abstract: A new technique for maintaining single-frequency output from injection-seeded Nd:YAG lasers is described. It involves quickly sweeping the slave-cavity longitudinal-mode spectrum when the flash lamps have created a maximum population inversion. An interference signal is detected by fast electronics, and the Q switch is opened when the slave cavity is resonant with the injected field.
TL;DR: A method for designing apodizers that increase the depth of focus and reduce the influence of spherical aberration are proposed.
Abstract: We propose a method for designing apodizers that increase the depth of focus and reduce the influence of spherical aberration. These two properties are explicitly manifested in computer-generated pictures and values of the Strehl ratio for variable spherical aberration.
TL;DR: Fourier-transform-limited, picosecond optical square pulses are generation by masking the amplitude and the phase of the optical frequency components, which are spatially dispersed within a grating pulse compressor.
Abstract: We report the generation of Fourier-transform-limited, picosecond optical square pulses (with a duration of ~6 psec full width at half-maximum and a rise time of ~1 psec). Control of the pulse temporal profile is achieved by masking the amplitude and the phase of the optical frequency components, which are spatially dispersed within a grating pulse compressor.
TL;DR: It is shown that efficient subpicosecond energy extraction is possible and the means of producing ultrashort seed pulses for the KrF* amplifier system and characteristics of the full system are described.
Abstract: A subpicosecond KrF* laser system capable of producing 20 ± 2-mJ pulses has been developed. The means of producing ultrashort seed pulses for the KrF* amplifier system and characteristics of the full system are described. It is shown that efficient subpicosecond energy extraction is possible.
TL;DR: The on-axis intensity response of a confocal scanning optical microscope was measured and the invariance of the shape of the central lobe to surface roughness and tilt is demonstrated.
Abstract: The on-axis intensity response of a confocal scanning optical microscope was measured for an objective of numerical aperture 0.9. The data compare favorably with theoretical calculations obtained by numerical integration of the standard theory, provided that lens aberrations are taken into account. The invariance of the shape of the central lobe to surface roughness and tilt is also demonstrated.
TL;DR: The use of photorefractive four-wave mixing for coupling and locking of lasers is discussed and a demonstration of the double phase-conjugate mirror and the semilinear passive phase- Conjugate Mirror, pumped simultaneously by different lasers, is described.
Abstract: We discuss the use of photorefractive four-wave mixing for coupling and locking of lasers. A demonstration of the double phase-conjugate mirror and the semilinear passive phase-conjugate mirror, pumped simultaneously by different lasers, is described. Cleanup of a distorted laser beam using another local laser and configurations for the phase locking of lasers are discussed.
TL;DR: The geometric rotation of the polarization angle in a ideal cylindrical optical fiber without birefringence is obtained for arbitrary fiber paths in terms of the image of the path in the tangent vector space.
Abstract: The geometric rotation of the polarization angle in a ideal cylindrical optical fiber without birefringence is obtained for arbitrary fiber paths in terms of the image of the path in the tangent vector space. The result extends a recent result of Chiao and Wu [Phys. Rev. Lett. 57, 933 (1986)] restricted to paths with parallel ends, which was derived from Berry's phase in the adiabatic limit of quantum mechanics [Proc. R. Soc. London Ser. A 392,45 (1984)]. The treatment given here is purely classical and uses differential geometry to extend earlier work by Ross [Opt. Quantum Electron. 16, 455 (1984)] on the uniform helix.
TL;DR: This approach clearly shows the possibility of realizing a new class of devices, namely, a linear coherent amplifier–mixer and an optically activated polarization switch or a phase-sensitive optical discriminator with high fanout.
Abstract: Exact solutions for the evolution of the state of polarization along a nonlinear single-mode birefringent fiber are given by means of the Poincare sphere representation. This approach clearly shows the possibility of realizing a new class of devices, namely, a linear coherent amplifier–mixer and an optically activated polarization switch or a phase-sensitive optical discriminator with high fanout.
TL;DR: A new approach to pure rotational coherent anti-Stokes Raman spectroscopy (CARS) and coherent Stokes Ramans spectroscope (CSRS) is demonstrated in which the pump and broadband Stokes lasers that are mixed have a large and arbitrary spectral separation.
Abstract: A new approach to pure rotational coherent anti-Stokes Raman spectroscopy (CARS) and coherent Stokes Raman spectroscopy (CSRS) is demonstrated in which the pump and broadband Stokes lasers that are mixed have a large and arbitrary spectral separation. In this method, the rotational Raman coherences are established by different frequency components within the single, broadband Stokes source. The narrow band then scatters from the excited coherences, producing CARS and CSRS simultaneously. We discuss phase matching for this new technique and its inherent advantages relative to pure rotational CARS as normally implemented.
TL;DR: A laser energy-scaling technique, based on a phase-conjugate oscillator/amplifier scheme that permits the coupling of several parallel amplifiers to form a single coherent output beam, is experimentally demonstrated.
Abstract: We have experimentally demonstrated a laser energy-scaling technique, based on a phase-conjugate oscillator/amplifier scheme that permits the coupling of several parallel amplifiers to form a single coherent output beam. This, is achieved despite dramatic differences in the individual amplifier energies and optical path lengths. When many amplifiers are coupled together, energy can be scaled significantly beyond the limit imposed by the maximum available volume of a single active medium. Although the present demonstration utilized Nd:YAG, this technique is quite general and can be applied to a variety of laser media.