Ceramic Reflector

Solid-state lasers include all optically pumped lasers in which the gain medium is a solid at room temperature.
 
 Customer requirements will differ dependant upon the type of laser, laser rod, source radiation (and source power) being employed and the particular end use of the laser. All, however, require a high reflectance material to form the pumping chamber cavity surrounding the laser rod and lamp. The efficiency in transfer of radiation from the source to the laser rod (referred to as optical coupling) determines to a large extent the overall efficiency of the laser system. The cavity walls must therefore have a high reflectivity at the absorption bands of the laser material.

Ceramic reflectors supplied by us work particularly well in Ruby and Nd:YAG laser pumping chambers and can be a highly cost effective alternative to metal coated reflectors. They are also used extensively as reflectors in housings for high intensity lamps.

• resists chemical attack

• has high strength

• has a high reflectivity over a broad wavelength band

• has good thermal conductivity and

• excellent dimensional and electrical stability at all operating temperatures.

Independent tests on our alumina have shown reflectance figures in excess of 96% (typically 97-98%) over the 500 nm to 2000 nm wavelengths. The material provides a highly diffuse reflectance, behaving as a bulk reflector of the source radiation by both reflecting and refracting light back into the cavity.

Pump radiation that has a longer wavelength than the stimulated emission does not contribute to the laser output but does heat up the laser crystal, which causes optical distortions affecting the quality of the laser output. For this reason cavities are therefore often water or liquid cooled and so need to be able to withstand the erosive action of the fluid, absorb the generated heat and remain dimensionally stable.

Our reflectors can be glazed both inside the cavity and around the outer edges using a highly reflective glaze that seals the ceramic against ingress of cooling fluids that may alter the refractive index, introduce impurities and reduce reflectance and efficiencies. Glazes can also act as filters andouryellow glazed reflectors have been used successfully in certain applications. The visible yellow colour is complementary to the spectral colours violet and indigo and effectively absorbs these wavelengths up to around 450 nm.

Properties of Ceramics

A porous alumina ceramic of 99.7% Al2O3content, used extensively for long-life laser reflectors. This material is sintered at high temperatures to achieve a controlled porosity.

Prime features

• Surfaces can be sealed and coated with a solarization-resistant glaze to give high bulk reflectivity

• 97.8% reflectance efficiency at 1000nm

• Reflectance efficiency exceeds 96% across the wavelength range 500-2000nm(see curve)

• Controlled porosity

• Good thermal conductivity

• High electrical resistivity

Typical applications

Pumping chambers for Nd:YAG lasers — low to high power, single or multiple lamp designs. Pumping chamber reflectors of this material are virtually indestructible, and prove a highly cost effective alternative to metal coated types.

Production capabilities

• Components up to250mmlong and80mmwide/diameter manufactured as standard

• Larger components manufactured to development contracts

• One-piece or split-cavity designs

• Prototype, batch and volume production

Physical properties

• Color: White

• Bulk density (fired), Mg/m3 : 3.2

• Porosity (apparent), % nominal: 20

• Flexural strength (ASTM C1161, 3-point), MPa: 150

• Thermal expansion coefficient 200-500C, 10-6/C: 7.9 200-1000C, 10-6/C:9.0

2. Ceramic Reflectors For Lamp-pumped Solid-state Lasers

• BAB– the external shape is round;

• ZAB– the external shape is irregular

• LAK– the external shape is rectangular but one side is concave;

• EAB- the external shape is rectangular

• GAZ- the external shape is triangular

Remark: 1) unit: mm; 2) Distance means the distance between lamp and rod in sing-lamp configuration and the distance between two lamps in dual-lamp configuration.

3. Ceramic Reflectors For Diode-pumped Solid-state Lasers

Description of part number: CRDP-XX-YY-Z-AAA-BBB

• CRDP: ceramic reflector for diode-pumped solid-state laser

• XX – internal diameter of the reflector in mm.

• YY -  reflector length in mm.

• Z – number of the diodes to be placed around the laser rod.

• AAA – related to the cross section of the reflector such as TRI (triangle shape), CRL (round shape), PLT (plate shape)

• BBB – variant for remarks

4. Ceramic Reflectors For Beauty and IPL Applications:

Description of part number: CRIPL-XX-YY-BBB

• CRIPL: ceramic reflector for beauty and IPL applications

• XX – internal diameters or angler of the reflector in mm/degree

• YY -  reflector length in mm.

• BBB – variant for remarks

As far as the IPL parts are concerned, there are many “variation on the same theme” in order words the angle may beslightlydifferent, length could vary and some parts have no holes, others have several holes.  Parts could also be glazed or un-glazed.  We can make any parts and we could adapt the drawings to customer’s requirements’.

5. STG Series Ceramic Reflectors

STG series Ceramic reflectors are made by 99% Al2O3 and were fired at a proper temperature to retain the porosity and strength. The surface of the ceramic reflectors had adopted the technology of fully coating of high reflectivity ceramic glaze. And the reflector is diffuse reflection. To comparing with the gold-coating reflectors, the biggest advantage of the ceramic reflectors is in its extremely long life time. It’s a good solution for a part of the pump chamber which used on medical & industrial laser welding for the low cost and high efficiency.

Main features:

• Surface full glaze for maximum reflectivity and easy cleaning

• The reflectivity reaches 97% at the wavelength of 600-1000nm

• Reflectivity over 95% in the 400-1200nm spectrum

• The green body has proper porous and high strength properties

Main physical properties:

• Color: white

• Density: 3.1g/cm3 A kind of

• Porosity: 22%

• Bending strength: 170Mpa

• Coefficient of thermal expansion: 7.9×10-6­­/С (200～500℃), 9×10-6/С (200～1000℃)

Spectrum testing chart

Following is our existing models which are already used.

• STG-BAB – the external shape is round;

• STG-ZAB – the external shape is irregular

• STG-LAK – the external shape is rectangular but one side is concave;

• STG-EAB - the external shape is rectangular

• STG-GAZ - the external shape is triangular

We can customize the reflectors according to the drawings which are supplied by the customers. Please feel free to contact us if you have any specific requirements or applications.