Other

Government of the United States of America, As Represented by the Secretary of Commerce

University of Colorado

Leland Stanford Junior University

University Patents, Inc.

Bromac Enterprises

John L Hall

Jun Ye

Long-Sheng Ma

Scott A Diddams

Thomas Michael Baer

Peter J Martin

Henry C Kapteyn

Margaret Mary Murnane

Robert K Shelton

Mark Notcutt

Leo W Hollberg

Frank V Kowalski

Theodor W Hansch

Steven Cundiff

Siu Au Lee

Jon H Shirley

Ma Long-sheng

David J Jones

Miao Zhu

Mark L Eickhoff

Michael P Winters

A technique for reducing the vibration sensitivity of laser-stabilizing optical reference cavities is based upon an improved design and mounting method for the cavity, wherein the cavity is mounted vertically. It is suspended at one plane, around the spacer cylinder, equidistant from the mirror ends of the cavity. The suspension element is a collar of an extremely low thermal expansion coefficient material, which surrounds the spacer cylinder and contacts it uniformly. Once the collar has been properly located, it is cemented in place so that the spacer cylinder is uniformly supported and does not have to be squeezed at all. The collar also includes a number of cavities partially bored into its lower flat surface, around the axial bore. These cavities are support points, into which mounting base pins will be inserted. Hence the collar is supported at a minimum of three points.

Mounting system for optical frequency reference cavities

Disclosed is a system and method for stabilizing the carrier-envelope phase of the pulses emitted by a femtosecond mode-locked laser by using the powerful tools of frequency-domain laser stabilization. Control of the pulse-to-pulse carrier-envelope phases was confirmed using temporal cross correlation. This phase stabilization locks the absolute frequencies emitted by the laser, which is used to perform absolute optical frequency measurements that were directly referenced to a stable microwave clock.

Mode-locked pulsed laser system and method

Accurate and efficient synchronization of two pulsed radiation sources (e.g. iwo mode locked lasers) is accomplished in stages. Rough synchronization is accomplished by synchronizing (for example) the fundamental repetition rate of the two lasers. Fine synchronization is accomplished by synchronizing high harmonics of the two lasers. More accurate synchronization may be accomplished by adding more stages, by utilizing light out of a nonlinear laser in which the two beams are crossed, or by utilizing heterodyne beats of the two laser beams. A dc offset signal may added to the control signal generated by the synchronization stages.

Multistage synchronization of pulsed radiation sources

An ac technique for cavity ringdown spectroscopy permits 1&times;10 absorption sensitivity with microwatt light power. Two cavity modes are provided temporally out of phase such that when one mode is decaying, the other mode is rising. When one of the modes probes intra-cavity absorption of a sample gas, heterodyne detection between the two modes reveals dynamic time constants associated with the cavity and the cavity plus intra-cavity absorption. The system and method provides a quick comparison between on-resonance and off-resonance modes and enables sensitivities that approach the shot-noise limit.

Cavity ringdown spectroscopy system using differential heterodyne detection

Infectious wastes originating in hospitals or other locations are deposited into a sealable, pressure resistant, portable sterilizer vessel at the source of the wastes. The sterilizer vessel rides on wheels enabling travel of the filled vessel to a sterilization station at another location where steam is directed into the vessel to perform the sterilization. Operators need not transfer unprocessed infectious waste from a collection cart to a fixed sterilization vessel at the sterilization site. In the preferred form, handler exposure to unprocessed wastes is further reduced by creating an airflow from the vessel opening to a filter while the vessel is opened for deposit of wastes.

Biohazardous waste source sterilizer system and processing method

A low-loss comb-generating optical cavity including an optical amplifier and a microwave-driven electro-optic modulator crystal, produces a comb of optical frequency sidebands having spectral lines equally spaced around the frequency of an input laser beam incident on the comb-generating cavity. The comb-generating cavity includes an input mirror movable along the beam propagation direction, and a fixed position output mirror located at time synchronous distances of both the input laser wavelength and modulation wavelength. The comb-generating cavity and its microwave driven modulator are in resonance with the input laser beam, and provide iterative or recirculating beam action that transfers the input optical frequency of the laser, sideband by sideband, to remote and precisely known comb frequencies offset from, and centered on, the input laser frequency. Optical parametric amplification within the comb-generating cavity extends the sideband or comb spectrum and sharpens the time domain impulse represented by the cavity circulating fields. A relatively short bandpass filter optical cavity receives the comb output of the comb-generating cavity and is made up of the fixed-position mirror and a third mirror movable along the beam propagation direction. Fine movement of the third mirror tunes the bandpass filter cavity, and preferentially couples out the power of one or more comb frequencies. An optional input optical cavity at the input side may increase efficiency. A self-oscillating configuration provides optical parametric oscillation.

Comb generating optical cavity that includes an optical amplifier and an optical modulator

A revolving trommel situated adjacent to a shredder has an annular screen which intercepts oversized or elongated fragments in the outflow from the shredder for return to the shredder. A first fragment guide directs the shredder outflow into the trommel and vanes in the trommel lift the oversized fragments to another fragment guide which extends out of the trommel to the shredder intake. In the preferred form, the trommel rests upon and is turned by a motor driven flexible continuous belt which carries fragments that pass through the screen upward to an elevated discharge chute. The apparatus is particularly useful for fragmentizing sterilized medical wastes.

Fragment recirculating shredder

Infectious wastes from hospitals or other sources are sterilized in a chamber which is pivotable between a waste loading orientation, a sterilizing orientation and a waste dumping orientation. The chamber is attached to a framework by first and second pairs of pivot arms which are coupled to the sides of the chamber at spaced apart locations. An actuator swings the first arms upward to bring the chamber to the loading orientation and swings the arms downward to turn the chamber to the dumping orientation. The pivot arm arrangement causes the chamber as a whole to lower as it turns towards the loading orientation and to rise as it turns towards the dumping orientation. This reduces the amount of lifting of materials that is required during loading operations while also providing adequate clearance under the chamber for dumping operations. In one form, the chamber is translatable horizontally between a waste sterilizing location at which a chamber sealing door is situated and a loading and dumping location situated over a waste compactor intake compartment. A plurality of the chambers may be in side-by-side relationship and be loaded, operated and dumped at different times thereby enabling a continuous inflow of waste material.

Apparatus for processing bio-harzardous waste

Apparatus for treating infectious wastes from hospitals, medical clinics or the like integrates sterilizing, fragmentizing and compaction steps within a single waste processor. Wastes which are deposited in a sterilization chamber are made non-infectious by exposure to pressurized steam. An outflow of wastes from the sterilization chamber is fed through one or more on-line shredders or the like and then into a compactor which compresses the processed material into a transportable container that may be hauled to a dump site.

Unitized infectious waste processor and waste processing method

A fluid tight waste materials receptacle is located within a housing which has an upper access opening through which infectious wastes from medical clinics or the like may be deposited in the receptacle. A lower access opening enables entry and withdrawal of a sterilized waste receiver which may, for example, be a wheeled cart. The receptacle has an open end and a closed end and is pivotable between a first orientation at which the open end is coincident with the upper access opening in order to receive wastes and a second orientation at which the open end is turned downward to discharge wastes into the receiver. A closure pivoted to the housing seats in and seals the open end of the receptacle when it is at the first orientation. The receptacle is periodically evacuated and steam is admitted to sterilize the contents prior to discharge into the receiver.

Apparatus for storing and sterilizing bio-hazardous waste

Apparatus for fragmentizing objects recovers and reprocesses oversized fragments. A shredder is encircled by an annular trommel revolving about a horizontal axis of rotation and which extends over the shredder intake hopper and below the fragment outlet. Fragments which are too large to pass through apertures in the trommel are carried upward by vanes on the trommel and returned to the intake hopper. In one form of the apparatus, a fragment guide has a curved surface extending along at least a lower portion of the trommel and which is spaced from the trommel to allow small fragments to pass through the trommel apertures. Cleats on the trommel urge such fragments towards a fragment discharging end of the guide. Thin elongated fragments which attempt to pass through a trommel aperture are stopped by the presence of the guide and thus are also carried upward and returned to the intake for further processing.

Recirculating shredder

Hospital wastes or the like are sterilized and compressed for disposal by apparatus having a waste receptacle with a waste receiving opening at the top and having a sterilizer casing, the receptacle and casing being in telescoping relationship. The receptacle initially protrudes from the casing in order to receive the wastes and is then translated into the casing to close the casing and thereby enable sterilization of the contents by admission of pressurized steam. A helical rotary conveyer extends along the axis of the receptacle and has several functions. The conveyer moves wastes from the receptacle into the casing and precompacts such wastes prior to the sterilization cycle and may be used to stir the wastes during sterilization. After opening of a casing door, the conveyer operates to discharge the sterile wastes from the casing and a translatable ram forces the material into an adjacent compactor container.

Bio-hazardous waste sterilizer and compactor

A highly accurate in-situ determination of the refractivity of an ambient atmosphere is disclosed, which determination is utilizable to enhance the accuracy of a quantity measurement. The system includes use of a refractometer exposed to an ambient atmosphere and having light directed thereto to form an optical interference fringe pattern having a dependence upon the refractivity of the ambient atmosphere. The fringe pattern is measured as a function of angle either by sequentially scanning a collimated input beam in angle while collecting and detecting the transmitted light, or by imaging (onto a multi-element detector) the angular exit space of the interferometer illuminated with a diverging input beam. The electrical output of the detector is processed to provide an output indicative of the index of refraction of the ambient atmosphere. The determined index of refraction is utilizable to enhance the accuracy of a quantity measurement, such as, for example, the distance measurement provided by a Fabry-Perot or displacement-measuring Michelson interferometer.

Highly accurate in-situ determination of the refractivity of an ambient

The disclosure is directed to a method and apparatus for precisely controlling the frequency of a laser, and for precise control of distance. In a disclosed embodiment, a laser beam is split, modulated to obtain a frequency differential, and coupled to an interferometer which is designed to produce two processed beams having intensities that vary at the same ac frequency, but at a phase difference that is indicative of the laser frequency. The processed beams are converted to ac electrical signals which are coupled to phase control circuitry. The phase control circuitry determines the phase between the electrical signals and produces a control signal for controlling the laser frequency. Phase offset increments are introduced in the phase detection process, these phase offset increments resulting in controlled changes in the laser frequency. The laser frequency can be computed and read out as a function of the phase offset increments. In another embodiment, the control signal is used to accurately control a distance.

Method and appartus for laser control

An external laser frequency stabilizer combines an acousto-optic frequency shifter and a fast electro-optic phase modulator. A compensating electronic delay line in a crossover network provides a near-ideal transducer response while keeping the voltage across the electro-optic crystal away from the amplifier limits.

Growing community of inventors

Boulder, CO, United States of America

John L Hall