Abstract: Disclosed are a polyethylene glycol conjugate drug, and a preparation method therefor and the use thereof. Specifically, the present invention relates to a polyethylene glycol conjugate drug represented by formula A or a pharmaceutically acceptable salt thereof, a method for preparing the polyethylene glycol conjugate drug or the pharmaceutically acceptable salt thereof, an intermediate for preparing the polyethylene glycol conjugate drug or the pharmaceutically acceptable salt thereof, a pharmaceutical composition comprising the polyethylene glycol conjugate drug or the pharmaceutically acceptable salt thereof, and the use of the polyethylene glycol conjugate drug or the pharmaceutically acceptable salt thereof in the preparation of a drug.

Abstract: A mode locked laser supplies a high repetition seed pulse train along a seed beam path to a pulse picker having at least one polarizer. A Faraday rotator in optical communication with the seed beam rotates the polarization of the seed beam by about 45°. A double pass acousto optical modulator (AOM) receives the seed beam propagating through the Faraday rotator and diffracts the seed beam into a first order first pass beam and a zero order first pass beam. A reflector returns the first pass first order beam into the acousto optical modulator for a second pass. The modulator diffract the beam into a zero order second pass beam and a first order second pass diffracted beam, the first order second pass beam propagating on the substantially same path as the incoming seed beam but in the opposite direction.

Abstract: A mode locked laser supplies a high repetition seed pulse train along a seed beam path to a pulse picker having at least one polarizer. A Faraday rotator in optical communication with the seed beam rotates the polarization of the seed beam by about 45°. A double pass acousto optical modulator (AOM) receives the seed beam propagating through the Faraday rotator and diffracts the seed beam into a first order first pass beam and a zero order first pass beam. A reflector returns the first pass first order beam into the acousto optical modulator for a second pass. The modulator diffract the beam into a zero order second pass beam and a first order second pass diffracted beam, the first order second pass beam propagating on the substantially same path as the incoming seed beam but in the opposite direction.

Abstract: A mode locked laser supplies a high repetition seed pulse train along a seed beam path to a pulse picker having at least one polarizer. A Faraday rotator in optical communication with the seed beam rotates the polarization of the seed beam by about 45°. A double pass acousto optical modulator (AOM) receives the seed beam propagating through the Faraday rotator and diffracts the seed beam into a first order first pass beam and a zero order first pass beam. A reflector returns the first pass first order beam into the acousto optical modulator for a second pass. The modulator diffract the beam into a zero order second pass beam and a first order second pass diffracted beam, the first order second pass beam propagating on the substantially same path as the incoming seed beam but in the opposite direction.

Abstract: A mode locked laser supplies a high repetition seed pulse train along a seed beam path to a pulse picker having at least one polarizer. A Faraday rotator in optical communication with the seed beam rotates the polarization of the seed beam by about 45°. A double pass acousto optical modulator (AOM) receives the seed beam propagating through the Faraday rotator and diffracts the seed beam into a first order first pass beam and a zero order first pass beam. A reflector returns the first pass first order beam into the acousto optical modulator for a second pass. The modulator diffract the beam into a zero order second pass beam and a first order second pass diffracted beam, the first order second pass beam propagating on the substantially same path as the incoming seed beam but in the opposite direction.

Abstract: A method and apparatus for spatially separating beams with different wavelengths is presented. The system includes: a light source (i.e. a laser with multiple harmonic output beams) with multiple wavelengths emitted along a single beam path or very nearly collinear beam paths, a path which connects the light source to a wavelength dependent beam separator, and a second path for blocking unwanted output wavelengths which connects the beam separation region to the laser output.

Abstract: A tunable OPO laser is provided. The laser includes an OPO cavity containing an OPO nonlinear crystal for generating a plurality of preselected wavelength beams of different wavelengths. The OPO cavity is formed between a first OPO reflective surface and a second OPO reflective surface. A laser cavity containing a lasing medium for generating a preselected wavelength fundamental beam is provided in optical communication with the OPO cavity. The laser cavity is partially separate and partially overlapping the OPO cavity. A beam separating prism is located in the overlapping portion of the two cavities. The beam separating prism separates electromagnetic radiation propagating through the prism into spatially separate paths of different wavelength. At least one of the OPO reflecting surfaces is moveable over a preselected range to reflect a selected wavelength of electromagnetic radiation propagating from the prism for amplification in the OPO cavity.

Abstract: According to the invention, a diode side pumped laser is provided. The laser has an optical cavity formed between a first and a second reflective surface. A Nd:YLF lasing medium is located within the cavity along its optical axis. The Nd:YLF lasing medium can desirably be a single Nd:YLF lasing rod which has a length of 90 mm or more. A plurality of diode bars are provided in optical communication with the Nd:YLF lasing medium preferably a lasing rod. The diode bars extend along substantially the pumpable length of the lasing rod and radially around the periphery of the lasing rod. The diode bars have radiation outlets in optical communication with the lasing rod for supplying electromagnetic radiation on pumping paths to the rod. The lasing rod receives an average linear power density from the diode bars of less than 50 watts/cm. The pumping paths traverse substantially the entire pumpable length of the lasing rod substantially perpendicular to the direction of propagation of energy in the laser cavity.

Abstract: A high power pulsed laser having a Q-switched seed laser lasing at a preselected wavelength at TEM00 mode to produce a pulsed seed beam is disclosed. One or more substantially non-depolarizing optical amplifier media namely Nd:YVO4 or Nd:GVO4 crystals are used in optical communication with the seed laser. The optical amplifier media has a stimulated emission spectrum overlapping the preselected wavelength. A pumping source is provided in optical communication with the optical amplifier media to supply 15 watt or more of pumping power to excite the amplifier media and amplify the pulsed seed beam. The resulting laser produces 15 watts or greater of output power at the preselected wavelength. A temperature controller is desirably provided to regulate the temperature of the optical amplifier medium within a preselected range selected to enhance the amplification of the seed beam by increasing the degree of overlap between the stimulated emission spectrum and the seed beam wavelength.

Abstract: A high pulse energy, side pumped laser is provided. The laser has an optical cavity formed between a first and a second reflective surface. A lasing medium is located within the cavity along its optical axis. A plurality of diode bars are provided in optical communication with the lasing medium preferably a lasing rod. The diode bars supply electromagnetic radiation to the lasing rod. The diode bars are configured about the lasing rod so that electromagnetic radiation from the diodes bars propagates through the lasing rod on a plurality of substantially nonintersecting paths. Since the lasing rod is side pumped, the substantially nonintersecting paths traverse the lasing rod substantially perpendicular to the direction of propagation of energy in the laser cavity.

Abstract: A laser having an optical parametric oscillator for providing a preselected wavelength beam is provided. A nonlinear crystal cut for phase matching condition preferably cut for noncritical phase matching conditions for the fundamental beam wavelength and the preselected wavelength beam is located in both the optical parametric oscillator cavity and laser resonator cavity. The optical axis of the laser resonator and the optical axis of the optical parametric oscillator cavity are at least partially separate and partially overlap. The laser crystal is located in the laser resonator cavity but not in the optical parametric oscillator cavity. Each end of the OPO nonlinear crystal that intersects the optical axes has a Brewster cut for both the fundamental and preselected wavelength beams so that the fundamental and preselected wavelength beams incident on the nonlinear crystal at approximately the Brewster angle and pass through without substantial reflection loss.

Abstract: The invention relates to an improved harmonic laser which provides an externally generated harmonic beam. According to the invention, a third harmonic laser or higher harmonic laser is provided. The laser includes a first reflector and a second reflector for fundamental beam, forming a resonator cavity having an optical axis. The resonator includes a laser medium for producing a fundamental beam. The first reflector is highly reflective for fundamental beam. The second reflector is at least partially reflective for fundamental beam. A second harmonic generator is located within the resonator formed between the first high reflector and the second reflector for generating a second harmonic beam from the fundamental beam. Preferably the second harmonic generator is located so that the fundamental beam makes a first and second pass through the second harmonic generator. The resonator produces two output beams at least one of which is a harmonic beam.

Abstract: According to the invention, a laser and a method of operating a laser which can produce multiple pulses from a single laser head is provided. A lasing medium is pumped by pumping source such as laser diodes, lamp and such. A modulator located in the cavity is turned on to induce a loss in the laser cavity sufficient to prevent lasing. A first predetermined amount of energy is stored in the lasing medium while the modulator is turned on due to a creation of a population inversion in the lasing medium in excess of the lasing threshold. The modulator is then turned off for a period of time to allow the lasing medium to provide a first pulse. The modulator is then turned on before the population inversion in the laser medium is depleted completely so that a predetermined amount of energy remains stored in the lasing medium. After the first pulse, the modulator again induces a loss in the cavity sufficient to prevent lasing.

Abstract: Lasers are provided to deliver a wide variety of wavelengths at variable pulse energy. A laser cavity is formed between a first and second reflective surface. A lasing medium is located within cavity which lases at a preselected fundamental frequency. One or more nonlinear crystals are provided in optical communication with the lasing crystal to produce a secondary beam having a different frequency than the fundamental beam. A modulator is provided to control the pulse energy of the secondary beam. Desirably the secondary beam is a harmonic beam for example a second, third, fourth or fifth harmonic beam or a beam provided by an optical parametric oscillator.

Abstract: A laser beam includes a concave or convex mirror which is reflective for wavelength of the high intensity beam. The reflective mirror is located along a preselected path of a high intensity laser beam so that the high intensity laser beam intersects the mirror at a first position. A beam collimator is located in the path of the high intensity beam reflected by the concave or convex mirror. The concave or convex mirror is movably mounted desirably rotatably mounted in the path of the high intensity beam. Desirably the mirror is rotated about a preselected axis. Desirably, the axis is selected so that when the mirror is rotated to a new position, the high intensity beam will be reflected along the same path to the collimator as it was prior to any rotation.

Abstract: A matrix assisted laser desorption and ionization system is provided. The system includes a mass spectrometer for analyzing at least one sample. The mass spectrometer includes a sample receiving chamber for receiving a sample under a vacuum. A UV laser is provided for producing a UV beam along a first beam path that does not intersect with the sample. A beam expander is provided in optical communication with the UV laser beam to expand the diameter of the beam. A focusing system is provided in optical communication with the beam expander to focus the laser beam propagating from the beam expander to a predetermined minimum spot size. The focusing system is located along the path of the beam propagating from the beam expander so that the beam strikes the approximate optical center of the focusing system. A high reflecting mirror is provided in optical communication with the focused beam propagating from the focusing system to direct the focused beam to strike the sample at a preselected strike point.

Abstract: Harmonic lasers are provided. A third harmonic laser includes a first high reflector and an output coupler forming a resonator cavity having an optical axis. The resonator cavity includes a laser medium for producing a fundamental beam. Desirably, the laser medium is Nd:YAG, Nd:YLF, Nd:YV04, although other laser mediums are also contemplated such as Ti:sapphire, Nd:YAB and the like. The laser medium can be pumped by any desired source for example laser, laser diode, laser diode bar, fiber coupled laser diode bar or lamp which are well known in the art. The laser medium can be either end pumped or side pumped which are also well known. The first high reflector is reflective of a fundamental beam. A second harmonic generator is located within the cavity formed between the first high reflector and the output coupler for generating a second harmonic beam from the fundamental beam. The output coupler is highly transmissive for second harmonic beam and partially transmissive for a fundamental beam.

Abstract: According to the invention, a high power diode pumped solid state laser is provided. The laser includes a first and second reflective surfaces which form an optical resonator cavity. A laser medium, particularly a Nd doped laser medium for example: a Nd:YAG, a Nd:YLF, or a Nd:YVO4 crystal is provided within the laser cavity. A fundamental frequency laser beam propagates from the front and back ends of the laser medium. The first reflective surface is highly reflective for fundamental beam. The second reflective surface is at least partially reflective for fundamental beam. The laser medium is end pumped by at least one diode pumping apparatus for example, a laser diode, or diode array, or fiber coupled laser diodes, whose wavelength matches at least one laser medium absorption band. The diode pumping apparatus is located adjacent either the front end or the back end of the laser medium, or both. The optical resonator cavity is configured to provide a laser beam diameter in the laser medium from about 0.

Abstract: Harmonic lasers are provided. A third harmonic laser includes a first high reflector and an output coupler forming a resonator cavity having an optical axis. The resonator cavity includes a laser medium for producing a fundamental beam. Desirably, the laser medium is Nd:YAG, Nd:YLF, Nd:YV04, although other laser mediums are also contemplated such as Ti:sapphire, Nd:YAB and the like. The laser medium can be pumped by any desired source for example laser, laser diode, laser diode bar, fiber coupled laser diode bar or lamp which are well known in the art. The laser medium can be either end pumped or side pumped which are also well known. The first high reflector is reflective of a fundamental beam. A second harmonic generator is located within the cavity formed between the first high reflector and the output coupler for generating a second harmonic beam from the fundamental beam. The output coupler is highly transmissive for second harmonic beam and partially transmissive for a fundamental beam.

Abstract: According to the invention, a high power diode pumped solid state laser is provided. The laser includes a first and second reflective surfaces which form an optical resonator cavity. A laser medium, particularly a Nd doped laser medium for example: a Nd:YAG, a Nd:YLF, or a Nd:YVO4 crystal is provided within the laser cavity. A fundamental frequency laser beam propagates from the front and back ends of the laser medium. The first reflective surface is highly reflective for fundamental beam. The second reflective surface is at least partially reflective for fundamental beam. The laser medium is end pumped by at least one diode pumping apparatus for example, a laser diode, or diode array, or fiber coupled laser diodes, whose wavelength matches at least one laser medium absorption band. The diode pumping apparatus is located adjacent either the front end or the back end of the laser medium, or both. The optical resonator cavity is configured to provide a laser beam diameter in the laser medium from about 0.