Abstract: A system includes an apparatus having at least one permanent magnet and at least one magnetic field sensor at a pole of the at least one permanent magnet and configured to be positioned relative to a surface of a membrane containing immobilized magnetic particles selectively bound to an analyte such that the magnetic particles are magnetized by the at least one permanent magnet. The system further includes a stage configured to move at least one of the apparatus and the membrane relative to one another with an oscillatory movement parallel to the surface of the membrane, at least one controller configured to control the oscillatory movement, and a data acquisition unit configured to receive signals from the at least one magnetic field sensor and the at least one controller method.

Abstract: A pulse transformer for modifying the amplitude and phase of short optical pulses includes a pulse source and an adaptively controlled stretcher or compressor including at least one fiber Bragg grating (FBG) configured to receive pulses from the pulse source and having a first second-order dispersion parameter (D21). The pulse transformer further includes at least one optical amplifier configured to receive pulses from the FBG and a compressor configured to receive pulses from the at least one optical amplifier. The compressor has a second second-order dispersion parameter (?D22), an absolute value of the first second-order dispersion parameter (|D21|) and an absolute value of the second second-order dispersion parameter (|?D22|) that are substantially equal to one another to within 10%.

Abstract: Systems and methods for precision control of microresonator (MR) based frequency combs can implement optimized MR actuators or MR modulators to control long-term locking of carrier envelope offset frequency, repetition rate, or resonance offset frequency of the MR. MR modulators can also be used for amplitude noise control. MR parameters can be locked to external reference frequencies such as a continuous wave laser or a microwave reference. MR parameters can be selected to reduce cross talk between the MR parameters, facilitating long-term locking. The MR can be locked to an external two wavelength delayed self-heterodyne interferometer for low noise microwave generation. An MR-based frequency comb can be tuned by a substantial fraction or more of the free spectral range (FSR) via a feedback control system. Scanning MR frequency combs can be applied to dead-zone free spectroscopy, multi-wavelength LIDAR, high precision optical clocks, or low phase noise microwave sources.

Abstract: A method includes preparing a wafer including a substrate and a semiconductor structure, and irradiating an inner portion of the substrate at a predetermined depth in a thickness direction a plurality of times with laser pulses at a first time interval and a predetermined distance interval between irradiations. Each irradiation performed at the first time intervals in the step of irradiating the substrate with laser pulses includes irradiating the substrate at a first focal position in the thickness direction with a first laser pulse having a first pulse-energy; and after irradiating with the first laser pulse, irradiating the substrate with a second laser pulse performed after a second time interval, the second time interval being shorter than the first time interval and being in a range of 3 ps to 900 ps, and the second laser pulse having a second pulse-energy 0.5 to 1.5 times the first pulse-energy.

Abstract: Chirped pulse amplification (CPA) systems configured to generate and amplify multi-pulses are described. The nonlinear interaction of pulses can generate a multiple pulse pack with a dense time separation between pulses. Reducing or eliminating the nonlinear interaction can be provided by spectrally and/or temporally splitting pulses in the chirped amplification system.

Abstract: In an example amplifier system, an input pulse train is passed through an optical stage that splits each pulse into two or more pulses. These divided pulses are then injected into at least two amplifiers for amplification. The amplified pulses are subsequently passed back through the same optical stage in order to combine the pulses back into one high energy pulse. The amplifier system can use time division multiplexing (TDM) and/or spatial division multiplexing (SDM) to produce, e.g., four pulses in conjunction with two amplifiers and propagation through two optical beam splitters, which are coherently combined into a single output pulse after amplification. The amplifiers can comprise fiber amplifiers or bulk amplifiers.

Abstract: Examples of compact control electronics for precision frequency combs are disclosed. Application of digital control architecture in conjunction with compact and configurable analog electronics provides precision control of phase locked loops with reduced or minimal latency, low residual phase noise, and/or high stability and accuracy, in a small form factor.

Abstract: A method includes preparing a wafer including a substrate and a semiconductor structure, and irradiating an inner portion of the substrate at a predetermined depth in a thickness direction a plurality of times with laser pulses at a first time interval and a predetermined distance interval between irradiations. Each irradiation performed at the first time intervals in the step of irradiating the substrate with laser pulses includes irradiating the substrate at a first focal position in the thickness direction with a first laser pulse having a first pulse-energy; and after irradiating with the first laser pulse, irradiating the substrate with a second laser pulse performed after a second time interval, the second time interval being shorter than the first time interval and being in a range of 3 ps to 900 ps, and the second laser pulse having a second pulse-energy 0.5 to 1.5 times the first pulse-energy.

Abstract: Systems and methods for stabilizing mid-infrared light generated by difference frequency mixing may include a mode locked Er fiber laser that generates pulses, which are split into a pump arm and a wavelength shifting, signal arm. Pump arm pulses are amplified in Er doped fiber. Shifting arm pulses are amplified in Er doped fiber and shifted to longer wavelengths in Raman-shifting fiber or highly nonlinear fiber, where they may be further amplified by Tm doped fiber, and then optionally further wavelength shifted. Pulses from the two arms can be combined in a nonlinear crystal such as orientation-patterned gallium phosphide, producing a mid-infrared difference frequency, as well as nonlinear combinations (e.g., sum frequency) having near infrared and visible wavelengths. Optical power stabilization can be achieved using two wavelength ranges with spectral filtering and multiple detectors acquiring information for feedback control. Controlled fiber bending can be used to stabilize optical power.

Abstract: Examples of systems and methods for integrated photonic broadband microwave transceivers are disclosed based on integrated coherent dual optical frequency combs. In some cases, when the system is configured as a transmitter, multiple radio frequency (RF) carriers can be generated, which can either be encoded independently, or used for broadcasting the same information into different bands. In some cases, when the system is configured as a receiver, the spectrum of the input signal can be sliced into several spectral segments for low-bandwidth detection and analysis. In some systems, the optics-related functionalities can be achieved via integrated optic technology, for example based on silicon photonics, providing tremendous possibilities for mass-production with significantly reduced system footprint.

Abstract: Low phase noise radio frequency (RF) sources generated by voltage controlled oscillators (VCOs) are described. Optical modulators driven by a VCO may be used to generate optical side-bands to cw lasers. The spectral extent of said side-bands can be increased via frequency broadening in highly nonlinear waveguides. Free running mode locked low phase noise comb oscillators can be used as reference oscillators to generate beat signals between those side-bands and individual comb modes at distal spectral regions, thereby creating an error signal used to reduce the phase noise of VCOs and the generation of low phase noise RF signals. VCO phase noise may be reduced by using free-running modelocked comb lasers phase locked to external frequency references, by omitting a reference comb and using a nonlinear interferometer for generating an error signal, or by locking a slave comb to the modulation frequency of an intra-cavity modulator driven by the VCO.

Abstract: Embodiments of optical fiber may include cladding features that include a material (e.g., fluorine-doped silica glass) that may produce a very low relative refractive index difference with respect to cladding material in which the cladding features are disposed. This relative refractive index difference may be characterized by (n1?n2)/n1, where n1 is the index of refraction of the cladding material in which the cladding features are included, and n2 is the index of refraction of the cladding features. In certain embodiments, the relative refractive index difference may be less than about 4.5×10?3. In various embodiments, the configuration of the cladding features including, for example, the size and spacing of the cladding features, can be selected to provide for confinement of the fundamental mode yet leakage for the second mode and higher modes, which may provide mode filtering, single mode propagation, and/or low bend loss.

Abstract: The invention describes classes of robust fiber laser systems usable as pulse sources for Nd: or Yb: based regenerative amplifiers intended for industrial settings. The invention modifies adapts and incorporates several recent advances in FCPA systems to use as the input source for this new class of regenerative amplifier.

Abstract: Holey fibers provide optical propagation. In various embodiments, a large core holey fiber comprises a cladding region formed by large holes arranged in few layers. The number of layers or rows of holes about the large core can be used to coarse tune the leakage losses of the fundamental and higher modes of a signal, thereby allowing the non-fundamental modes to be substantially eliminated by leakage over a given length of fiber. Fine tuning of leakage losses can be performed by adjusting the hole dimension and/or spacing to yield a desired operation with a desired leakage loss of the fundamental mode. Resulting holey fibers have a large hole dimension and spacing, and thus a large core, when compared to traditional fibers and conventional fibers that propagate a single mode. Other loss mechanisms, such as bend loss and modal spacing can be utilized for selected modes of operation of holey fibers.

Abstract: The present disclosure is directed to methods of preparing stable suspensions of precious metal nanoparticles and methods for attaching bio-molecules to the nanoparticles. The formation of nanoparticles can be accomplished by either chemical synthesis or pulsed laser ablation in a liquid. The present disclosure reveals the importance of controlling the conductivity of the dispersion medium during pulsed laser ablation in a liquid to control the particle size of the nanoparticles. The present disclosure also reveals the importance of adjusting and maintaining the conductivity in a range of 25 ?S/cm or less during storage of the nanoparticles and just prior to performing bioconjugation reactions. The control of conductivity is an important process for maintaining the nanoparticles as a stable non-aggregated colloidal suspension in a dispersion medium.

Abstract: A rechargeable energy storage device is disclosed. In at least one embodiment the energy storage device includes an air electrode providing an electrochemical process comprising reduction and evolution of oxygen and a capacitive electrode enables an electrode process consisting of non-faradic reactions based on ion absorption/desorption and/or faradic reactions. This rechargeable energy storage device is a hybrid system of fuel cells and ultra-capacitors, pseudo-capacitors, and/or secondary batteries.

Abstract: In certain embodiments a method and system for laser-based material processing of a material is disclosed. In at least one preferred implementation temporally overlapping pulse series are generated with separate pulsed laser sources, for example nanosecond (NS) and ultrashort pulse (USP) sources (NS-USP). Pulses are delivered to the material as a series of spatially and temporally overlapping pulse pairs. The material can, but need not, be a transparent material. In some applications of transparent material processing, it was found the combination of pulses both substantially more material modification and high machining quality than obtainable with either individual pulse series taken alone. Other micromachining methods and arrangement are disclosed for formation of fine features on or within a substrate. Such methods and arrangements may generally be applied with a NS-USP combination, or with other sources.

Abstract: In the present invention, a method of producing stable bare colloidal gold nanoparticles is disclosed. The nanoparticles can subsequently be subjected to partial or full surface modification. The method comprises preparation of colloidal gold nanoparticles in a liquid by employing a top-down nanofabrication method using bulk gold as a source material. The surface modification of these nanoparticles is carried out by adding one or multiple types of ligands each containing functional groups which exhibit affinity for gold nanoparticle surfaces to produce the conjugates. Because of the high efficiency and excellent stability of the nanoparticles produced by this method, the fabricated gold nanoparticle conjugates can have surface coverage with functional ligands which can be tuned to be any percent value between 0 and 100%.

Abstract: By compensating polarization mode-dispersion as well chromatic dispersion in photonic crystal fiber pulse compressors, high pulse energies can be obtained from all-fiber chirped pulse amplification systems. By inducing third-order dispersion in fiber amplifiers via self-phase modulation, the third-order chromatic dispersion from bulk grating pulse compressors can be compensated and the pulse quality of hybrid fiber/bulk chirped pulse amplification systems can be improved. Finally, by amplifying positively chirped pulses in negative dispersion fiber amplifiers, a low noise wavelength tunable seed source via anti-Stokes frequency shifting can be obtained.

Abstract: Various embodiments include large cores fibers that can propagate few modes or a single mode while introducing loss to higher order modes. Some of these fibers are holey fibers that comprise cladding features such as air-holes. Additional embodiments described herein include holey rods. The rods and fibers may be used in many optical systems including optical amplification systems, lasers, short pulse generators, Q-switched lasers, etc. and may be used for example for micromachining.