Methods for ultrashort pulse laser processing of optically transparent materials. A method for scribing transparent materials uses ultrashort laser pulses to create multiple scribe features with a single pass of the laser beam across the material, with at least one of the scribe features being formed below the surface of the material. This enables clean breaking of transparent materials at a higher speed than conventional techniques. Slightly modifying the ultrashort pulse laser processing conditions produces sub-surface marks. When properly arranged, these marks are clearly visible with side-illumination and not clearly visible without side-illumination. In addition, a method for welding transparent materials uses ultrashort laser pulses to create a bond through localized heating. The ultrashort pulse duration causes nonlinear absorption of the laser radiation, and the high repetition rate of the laser causes pulse-to-pulse accumulation of heat within the materials. The laser is focused near the interface of the materials, generating a high energy fluence at the region to be welded. This minimizes damage to the rest of the material and enables fine weld lines.

Transparent material processing with an ultrashort pulse laser

By doping an organic compound functioning as an electron donor (hereinafter referred to as donor molecules) into an organic compound layer contacting a cathode, donor levels can be formed between respective LUMO (lowest unoccupied molecular orbital) levels between the cathode and the organic compound layer, and therefore electrons can be injected from the cathode, and transmission of the injected electrons can be performed with good efficiency. Further, there are no problems such as excessive energy loss, deterioration of the organic compound layer itself, and the like accompanying electron movement, and therefore an increase in the electron injecting characteristics and a decrease in the driver voltage can both be achieved without depending on the work function of the cathode material.

Light Emitting Device

A review of the use of high power diode lasers in surface hardening

LiDAR (light detection and ranging) systems use one or more emitters and a detector array to cover a given field of view where the emitters each emit a single pulse or a multi-pulse packet of light that is sampled by the detector array. On each emitter cycle the detector array will sample the incoming signal intensity at the pre-determined sampling frequency that generates two or more samples per emitted light packet to allow for volumetric analysis of the retroreflected signal portion of each emitted light packet as reflected by one or more objects in the field of view and then received by each detector.

Methods and apparatus for object detection and identification in a multiple detector lidar array

An array-based light detection and ranging (LiDAR) unit includes an array of emitter/detector sets configured to cover a field of view for the unit. Each emitter/detector set emits and receives light energy on a specific coincident axis unique for that emitter/detector set. A control system coupled to the array of emitter/detector sets controls initiation of light energy from each emitter and processes time of flight information for light energy received on the coincident axis by the corresponding detector for the emitter/detector set. The time of flight information provides imaging information corresponding to the field of view. Interference among light energy is reduced with respect to detectors in the LiDAR unit not corresponding to the specific coincident axis, and with respect to other LiDAR units and ambient sources of light energy. In one embodiment, multiple array-based LiDAR units are used as part of a control system for an autonomous vehicle.

Methods and apparatus for array based lidar systems with reduced interference

The invention discloses a high power laser diode comprising a plurality of laser light emitters (2) and a plurality of light collimating means (33), wherein each of the laser light emitters (2) defines, in a direction perpendicular to a direction of propagation (32) of an output laser beam, a fast axis (y) and a slow axis (x), and wherein each of the light collimating means is associated with a laser light emitter and configured for collimating the output laser beam at least in a fast axis (y) direction. In order to enable a simple and cost-efficient assembly of the diode laser with collimating means, having a layered structure consisting of a plurality of plane-parallel substrates. For this purpose, the diode laser comprises planar substrate means (10, 30) which serves to precisely define a distance between a respective laser light emitter (2) and an associated light collimating means to the order of one or several millimetres and to support the collimating means (33) such that the optical axis of said laser light emitters are parallel to each other and for defining a precise location of emitters on the planar substrate (10), preferably at predetermined distance in fast axis direction between said laser light emitters. The collimating means is an array or multiple single of micro-optical lenses having a rear side which is bonded to the upper surface of the planar spacer means. The submounts of the light emitters (2) are mounted to the planar substrate means (10, 30) and to a heatsink (6).

High Power Diode Laser Having Multiple Emitters and Method for its Production

An optical arrangement is provided for balancing the beam of one or more high-power diode lasers (HP-DL) arranged one above another. The beam, which is known to diverge very differently in the direction of the pn junction and perpendicular to the pn junction of the emitters of an HP-DL arranged in a row is imaged at a point with high power density and high beam quality the arrangement. Present for this purpose are optical devices which spread out the radiation in a mutually offset fashion in the direction of the pn junction while the radiation is superimposed perpendicular to the pn junction.

Optical arrangement for balancing the beam of one or more high power diode lasers arranged one above another

An apparatus for shaping the output beam of a strip of lasers, or an array of such strips, comprising a first reflective member including at least a first reflective element for deflecting a first portion of the output beam in a first direction oriented at a first angle in the slow axis direction and at a second angle in the fast axis direction, and at least a second reflective member including at least a first reflective element for deflecting the first output beam portion from the first direction to a second direction in the Z axis. The output beam is thus shaped to define at least two beams comprising at least the first portion and a remainder of the output beam which is propagated along the Z axis without deflection by any reflective member, with the first portion of the output beam being oriented approximately parallel to the un-deflected remainder.

Apparatus for shaping the output beam of semiconductor lasers

The laser includes a laser bar (1) consisting of strips of semiconducting material divided optoelectrically into individual laser diodes (6.1-6.4). A heat sink with a substantially lower coefficient of thermal expansion than the laser bar, is soldered to the laser bar on the p-side (4) and a contact is joined to the bar on the n-side. The bar is soldered to the heat sink using a hard solder with low ductility at room temperature. The bar has breaks at certain intervals at defined positions between the laser diodes, which are physically separated into individual diodes and/or groups of diodes so that no mechanical stresses are transferred.

High power diode laser

Commercially available high power diode lasers (HPDLs) with output powers of up to 6 kW have been recognized as an interesting tool for industrial applications. In certain fields of application they offer many advantages over Nd:YAG and CO 2 lasers because of their low maintenance, compact design and low capital costs. Examples of successful industrial implementation of HPDLs include plastic welding, surface hardening and heat conduction welding of stainless steel and aluminum. The joining of plastics with an HPDL offers the advantages of producing a weld seam with high strength, high consistency and superior appearance. One example is the keyless entry system introduced with the Mercedes E-class where the microelectronic circuits are embedded in a plastic housing. Other applications include instrument panels, cell phones, headlights and tail lights. Applications in the field of surface treatment of metals profit from the HPDL's inherent line-shaped focus and the homogeneous intensity distribution across this focus. An HPDL system is used within the industry to harden rails for coordinate measurement machines. This system contains a customized zoom optic to focus the laser light onto the rails. With the addition of a temperature control, even complex shapes can be hardened with a constant depth and minimum distortion.

Stefan Heinemann

Papers

High Power Diode Laser Having Multiple Emitters and Method for its Production

Optical arrangement for balancing the beam of one or more high power diode lasers arranged one above another

Apparatus for shaping the output beam of semiconductor lasers

High power diode laser

Hardening and welding with high-power diode lasers