We demonstrate a technique for generating tunable all-optical delays in room temperature single-mode optical fibers at telecommunication wavelengths using the stimulated Brillouin scattering process. This makes use of rapid variation refractive index that occurs vicinity gain feature. The wavelength which induced delay is broadly by controlling laser pumping process, and magnitude can be tuned continuously as much 25 ns adjusting intensity pump field. applied to pulses short 15 ns. scheme...

The nature of pulse propagation through a material with negative value the group velocity has been mysterious, as simple models seem to predict that pulses will propagate "backward" such material. Using an erbium-doped optical fiber and measuring time evolution intensity at many points within fiber, we demonstrate peak does backward inside even though energy flow is always in forward direction.

We present the results of an experimental investigation transfer characteristics a fiber ring resonator for various values finesse. In particular, we measure spectral dependence intensity transmission and induced phase shift in undercoupled, critically coupled, overcoupled regimes. also demonstrate tunable optical (true time) group delay via show that high finesse is unnecessary. Our laboratory are excellent agreement with theoretical predictions.

We describe a new type of artificial nonlinear optical material composed one-dimensional metal-dielectric photonic crystal. Because the resonant nature multiple Bragg reflections, transmission within band can be quite large, even though through same total thickness bulk metal would very small. This procedure allows light to penetrate into highly metallic layers, leading large response. present experimental results for Cu/SiO(2) crystal which displays strongly enhanced response (up 12X) in...

We observe both extremely slow and superluminal pulse propagation speeds at room temperature in an erbium-doped fiber (EDF). A signal 1550 nm is sent through with varying powers of a 980 pump. The degree delay or advancement found to depend significantly on the pump intensity. maximum fractional 0.124 0.089. effect demonstrated for sinusoidally modulated Gaussian pulses. ability control sign magnitude velocity could have important implications applications photonics.

The distant projection of high-peak and average-power laser beams in the atmosphere is a long-standing goal with wide range applications. Our early proof-of-principle experiments [Phys. Rev. X 4, 011027 (2014)] presented one solution to this problem, employing energy deposition femtosecond filaments air sculpt millisecond-lifetime sub-meter-length waveguides. Here, we demonstrate waveguiding at 50-m scale, 60×longer, making many practical applications now possible. We employ new method for...

We demonstrate an all-optical delay line in hot cesium vapor that tunably delays 275 ps input pulses up to 6.8 ns and 740 59 (group index of approximately 200) with little pulse distortion. The is made tunable a fast reconfiguration time (hundreds ns) by optically pumping out the atomic ground states.

Polycrystalline ZnSe is an exciting source of broadband supercontinuum and high-harmonic generation via random quasi phase matching, exhibiting broad transparency in the mid-infrared (0.5-20 μm). In this work, effects wavelength, pulse power, intensity, propagation length, crystallinity on high harmonic are investigated experimentally using ultrafast pulses. Observed conversion efficiency scales linearly reaching as 36%. For first time to our knowledge, n2 measured for wavelengths ZnSe:...

We have constructed and characterized several optical microring resonators with scale sizes of the order 10 microm. These devices are intended to serve as building blocks for engineerable linear nonlinear photonic media. Light is guided vertically by an epitaxially grown structure transversely deeply etched air-clad sidewalls. report on spectral phase transfer characteristics such resonators. also observation a pi-rad Kerr shift accumulated in single compact ring resonator evidenced...

We have demonstrated that stimulated Brillouin scattering can be used to generate all-optical slow-light pulse delays of greater than a length for pulses as short 16 ns in single-mode fiber. Since the induced delay is generated wavelengths detuned from pump field by frequency, tuning near an electronic resonance material not required and thus at telecommunication wavelengths. This represents significant improvement over previous demonstrations slow light solids important step towards...

When a pulse superposed on cw background propagates through an erbium-doped fiber amplifier with negative group velocity, either broadening or compression can be observed. These effects explained in terms of two competing mechanisms: gain recovery and spectrum broadening. The distortion the shape caused by these depends input width, pump power, background-to-pulse power ratio. With proper choice three parameters, we obtain significant advancement minimal distortion.

We propose and demonstrate a proof-of-concept system for coherently combined multi-aperture slow-light laser radar. By employing delay elements in short-pulse-emitting systems to ensure synchronized pulse arrival at the target, we show that it is possible simultaneously achieve high resolution transverse lateral dimensions with wide steering angle.

In a single shot, we measure the full propagation path, including evolution to pulse collapse, of high power femtosecond laser propagating in air. This technique enables single-shot examination effect parameters that fluctuate on shot-to-shot basis, such as energy, duration, and air turbulence-induced refractive index perturbations. We find even lab over relatively short distances, turbulence plays significant role determining location collapse.

Abstract Nanofabrication offers promise for the design of artificial materials with optical properties unlike those occurring in nature and new exotic devices. We describe some specific ideas applications this area, present laboratory results on development these applications.

Polycrystalline materials can mediate efficient frequency up-conversion for mid-infrared light. Motivated by the need to understand properties of harmonic and supercontinuum radiation from such media, we utilize realistic numerical simulations reveal its complex temporal spatial structure. We show that generated propagates in form long-duration pulse trains be difficult compress optical filamentation high-energy pulses gives rise fine-structured beam profiles. identify trends concerning...

Femtosecond filaments deposit energy into air, leading to localized density depressions. We employ this effect with a multi-filamenting LG 01 beam generate long-lived air waveguides that guide high average power beams up ~50m.

We demonstrate the successful stabilization of type II chaos a multimode, intracavity frequency doubled, diode-pumped Nd:YAG (neodymium-doped yttrium aluminum garnet) laser in experiment using an adaptive proportional feedback control. The two orthogonal polarized infrared intensities are fed back to injection current pump diode. stability properties stabilized unstable fixed points investigated and exploited explain performance our control scheme determine suitable measurement signals for

We propose a multi-aperture slow-light laser radar with two-dimensional scanning. demonstrate experimentally that we can use two independent mechanisms, namely dispersive delay and stimulated Brillouin scattering, to dynamically compensate the group mismatch among different apertures, while optical phase locking control relative phases of signals emitted from as system steers beam in dimensions.

We describe a nonlinear optical mechanism that leads to decrease of the degree (transverse) spatial coherence laser beam as function propagation distance. This prediction is in direct contrast with those van Cittert-Zernike theorem, which applies through linear, homogeneous material. The by lost growth small phase irregularities initially present on wave front. develop detailed theoretical model this effect and experimental results validate model. practical importance result being able...

We demonstrate the tracking of an unstable periodic orbit (UPO) in a bronze ribbon experiment. The stabilization UPO at each step is performed via local control method, variant Ott-Grebogi-Yorke [Phys. Rev. Lett. 64, 1196 (1990)] feedback method. Starting with vectors extracted from analysis experimental data step, we redetermine location using adaptive correction that exploits applied signal and actual trajectory system. Doing so, can be tracked into parameter regime where chaotic attractor...