This article mainly describes the different polishing methods used for various crystals

After polishing the optical axis surface, it cannot be protected with white tape, but only black tape. Optical axis plane B=Ⅲ, finely grind with a glass plate, and finely grind about half of the aperture.

Polishing: tie it to the polished flat glass plate with silk cloth (silk cloth), make sure it is flat, then use 704 adhesive to coat the silk cloth evenly, put it on the flat glass plate when it is still wet and grind it lightly , and then wait for it to dry completely.

Sapphire and ruby: B=Ⅳ, θ=1′, N=1, ΔN=1/2.
Generally, a steel plate is used for polishing with abrasive paste, and the steel plate must be improved. If B has higher requirements, special plastic plates can be used. Must be finely ground.

For fine grinding, use boron carbide 280#, 20#. For polishing, use gem powder W2.5 to polish first, then use corundum powder W1.5 to polish, and use crystal as a cushion.

BBO, micro tide, scrub with 302#, 302.5#.
Grind on an iron or glass plate. CeO2 for polishing can be polished well. The crystal is easy to crack, so should pay more attention to maintaining a constant temperature during processing and before and after processing. And it is required to select unwrapped pure single crystal processing, with direction requirements. BBO crystal is soft and easy to be scratched, and the polished surface cannot be wiped with anything. BBO crystals are easy to deliquescence. After polishing, they are dried under infrared light, and then stored in a sealed and dry container.

Calcium fluoride (CaF2) B=Ⅲ, which can be polished with CeO2. Scrub with 302# and 303#, polish with gem powder, and then use diamond powder aqueous solution to polish the ring and Daozi. Use gem powder W1 to polish quickly, then use W0.5 to polish the ring and Daozi. Use polyamine resin as a polishing model, you can also use gem powder to polish and then polish with chrome oxide, and use a soft rubber plate for the plastic plate, and the workpiece should be polished the ring higher, but it does not need to be too high.

The hardness of the LBO material is similar to that of K9. Dispensing glue on the plate, such as sealing wax, can be directly sealed with an electric soldering iron. Grinding and polishing are similar to K9 glass, and polished with CeO2.

Lithium fluoride, lithium strontium: soft crystal, easy to break, B=Ⅱ, slowly heat the upper plate with infrared light. Do not wipe the surface too much when cleaning, otherwise it will be easy to get out. Lithium fluoride is used as a protective sheet, and W1.5 corundum powder is polished after polishing with W0.5 diamond micropowder aqueous solution. Polishing with CeO2 can also be polished. (500 mesh)

The hardness is similar to that of ZF, and ZF is used as a protective sheet for polishing. For KD*P and KT*P, use a soft rubber plate (usually a specially prepared rubber plate), or 1# (colder weather) and 2# (warmer weather) rubber plates, and use sand wash and edge down after polishing. KD*P is easy to deliquescence and brittle, and requires high temperature and humidity during polishing.

The double 45°LN electro-optical Q-switch is a rhomboid prism made of LN crystal. It has six processing surfaces, four of which are polished, and the other two only need to be oriented and ground. Among the four polished surfaces, the incident surface and the emergent surface are the crystal Y planes. The angle between the incident surface and the outgoing surface is 45°±1′, and the electrode surface is the X crystal surface, which must be plated with gold. During processing, the Y reference plane should be determined first. The diffraction angles of the X and Y crystal planes are θ(110)=17°24′ and θ(300)=31°12′. The upper plate is fixed with a plaster mold, and the plate material is LN or K9 glass similar to LN. During processing, the incident surface and the exit surface mainly control the geometric size and parallelism. The technical requirements are: N=1/4, B=III, θ≤10″. The first 45° reflective surface is processed mainly to control the angle and tower difference, and the second The 45° reflective surface not only controls the length of the part, but also controls the comprehensive parallelism of the light reflected by the four polished surfaces. Since the light is reflected four times inside the crystal, the measurement of the comprehensive parallelism is only a reticle 1/4n of the reading (n is the LN refractive index) usually requires θ≤10″. The roughness of the two 45° reflective surfaces of the LN electro-optic Q-switch is closely related to the resistance of the crystal to laser damage. LN belongs to ferroelectric crystal. When the polishing agent is not selected properly, it will not be polished or become rough again. You can choose a polishing agent with a high melting point or add HCL or soap powder to the solution. If it still does not work, you must re-sand.

Mg2SiO4 (forsterite) crystal, Mohs hardness is 7, polishing is difficult.
(1) It takes about 5~6 hours to polish with W3.5 and W2.5 gemstone grinding paste with polyamine resin hard plate, and it can be polished in about a day.
(2) Use W0.5 diamond micro-powder aqueous solution to change the aperture for bright and thick polishing. Low apertures are harder to change.

SeZn crystal, soft crystal. Use 302# and 302.5# for sanding on the glass plate, and use soft rubber plate for polishing, first polish with W1.5 corundum powder and then use W0.2 corundum powder solution for polishing, or polish with chrome oxide.

NaF sodium fluoride crystal, slightly deliquescence, does not require aperture, and the parallelism is average. Use 302.5# and 305# for sanding on the glass plate, and use polyurethane hard rubber plate for polishing and add W1, W0.5 abrasive paste. Then dry with silk and alcohol.

KCl crystal, slightly deliquescence, dry stick on the glass plate, grind it with 303# sand after sticking. More sand and less water. Generally, wipe it with a dry cloth, then wipe it with gasoline, and then polish it. Polishing does not need a rubber disc or wet CeO2 polishing. Apply dry CeO2 polishing. Tie the silk cloth to a flat glass, then put the CeO2 on the silk cloth and polish it with alcohol for about two hours. Be sure to dry the alcohol.
Note: Use a glass plate instead of an iron plate when frosting. For micro-moisture crystals such as NaCl and KBr, sandpaper is generally used for sanding, and after polishing with CeO2, corundum powder W0.2 is used for polishing.

Potassium arsenide – slightly poisonous, use 302#, 302.5# for sanding, use hard resin polishing mold for polishing, use W2.5 for grinding paste, and then use soft polishing mold, use W0.5 for grinding paste.

BGO is harder than LiF and much softer than YAG. BGO rods are polished with CeO2, but they are easy to get out of the way, and MgO is better for polishing.

YAB is about the same hardness as YAG, and the pads with the same polishing can be used universally.

LanYLi2O9 yttrium lanthanum aluminate, polished with W1.5 corundum powder, generally polished with gem powder or diamond powder, the polishing time is longer.

Lithium fluoride is fully decomposed and gypsum is applied. Glass plate for frosting.
polishing
(1) After polishing with W1.5 corundum powder aqueous solution, if need to change the parallelism, use corundum powder to correct it.
(2) Use Cr2O3 (Silkworm Baby Solution) to repair the finish. It is best to change the aperture from a high aperture to the bottom aperture. It should not be too high. It is best to avoid the cracking surface during rough grinding, preferably greater than 3°. It is best to use a soft plastic disc and protect it with transparent glue. TdJ E3/RAJ }ou|f|PQp

The hardness is similar to that of phosphorous glass, and it is easy to corrode. When polishing, use CeO2 to polish first, and then use Cr2O3 (silkworm solution) to repair the finish. Fluoride glass is generally not protected by protective paint. The surface that is sealed with wax can also be protected by transparent tape, and phosphor glass is used as a protective sheet.

YLF is yttrium lithium fluoride. Generally, infrared lamps are used for heating, but alcohol lamps cannot be used. Yellow wax cannot be used for protection with shell film. When heating, the infrared lamp is too close to be reliable, and the frosting is directly ground with 302.5#. After polishing with CeO2, use corundum powder W0.2 for polishing, and use a soft rubber disk for the rubber disk.

(1) Verticality: The hardness is similar to that of YAG rod, but it is polished with W1 when polishing. After polishing, there are blisters, and there is no way. The more polished, the more Daozi, there may be a chemical reaction. Throwing with W0.2 corundum powder aqueous solution and CeO2 have no result. Use Cr2O3 (silkworm baby solution) to completely throw away the trachoma and trachoma, the single aperture is not good, and it can be repaired with diamond powder W0.2 aperture.
(2) Parallelism: Generally, the pickaxe rod is placed on the flat glass after being sanded, and the parallelism is measured by a goniometer. Generally, the parallelism is 30′/grid. The difference between polishing is 4-5 grids, and the image is very blurred, so the parallelism is preferably between 3-4 grids.