Adjustable Beam Expander
CASTECH's adjustable beam expanders have a conventional working wavelength of 355nm, the magnification can be 2-10 times. It has many advantages, such as compact, divergent angle adjustable and the diameter of the output beam is large. It is widely used in laser processing. The product also has standard thread interface. In addition, it also can be customized to the working wavelength and appearance according to customer demand.
Beam expanders are optical devices used to increase the diameter of a collimated input beam to a larger collimated output beam. CASTECH's adjustable beam expanders have a conventional working wavelength of 355nm, the magnification can be 2-10 times. It has many advantages, such as compact, divergent angle adjustable and the diameter of the output beam is large. It is widely used in laser processing. The product also has standard thread interface. In addition, it also can be customized to the working wavelength and appearance according to customer demand.
Features: Applications:
◆ Fixed magnification ◆ Short pulse lasers
◆ Compact beam expanders ◆ Ultra-short pulse lasers
◆ For large beam diameters ◆ Laser scanning
◆ Customized design available
Specifications:
Material | Fused Silica | |
Wavelength | 355nm | |
Magnification | 2, 3, 4 | 5, 6, 7, 8, 10 |
Clear Input Aperture | 12mm, 8mm, 8mm | 8mm |
Clear Output Aperture | 26mm, 26mm, 20mm | 31mm |
Max. Input Beam Diameter | 10mm, 6mm, 4mm | 6mm, 4mm, 4mm, 3mm, 3mm |
Outside Diameter | 42mm | 46mm |
Total Length | 58mm | 86mm |
Screw Thread | M30×1 | M30×1 |
Transmission | >98% | >98% |
Divergence Adjustable | Yes | Yes |
Product specifications are subject to change without notice;
Customized (Wavelength, Dimension, Power Handling , etc) are available;
Note:All products are RoHS compliant.
Order No. | Magnification | Material | C.A.(φ) mm | Max exit(φ)mm | Outside (φ)mm | Length (mm) | Thread | Adjustable range(mrad) |
BE355-2-30-A/B | 2 | Fused silica | 12 | 26 | 42 | 58 | M30×1 | 0.02-2.6 |
BE355-3-30-A/B | 3 | Fused silica | 8 | 26 | 42 | 58 | M30×1 | 0.03-3.6 |
BE355-4-30-A/B | 4 | Fused silica | 8 | 20 | 42 | 58 | M30×1 | 0.05-5.2 |
BE355-5-30-A/B | 5 | Fused silica | 8 | 31 | 46 | 86 | M30×1 | 0.02-36 |
BE355-6-22-A/B | 6 | Fused silica | 8 | 31 | 43 | 80 | M22×0.75 | 0.03-43 |
BE355-6-30-A/B | 6 | Fused silica | 8 | 31 | 46 | 86 | M30×1 | 0.03-43 |
BE355-7-30-A/B | 7 | Fused silica | 8 | 31 | 46 | 86 | M30×1 | 0.09-50 |
BE355-8-22-A/B | 8 | Fused silica | 8 | 31 | 43 | 80 | M22×0.75 | 0.07-62 |
BE355-8-30-A/B | 8 | Fused silica | 8 | 31 | 46 | 86 | M30×1 | 0.07-62 |
BE355-10-30-A/B | 10 | Fused silica | 6 | 31 | 46 | 86 | M30×1 | 0.1-70 |
BE-355-2-30-B:
BE-355-5-30-B:
Beam expanders are optical devices used to increase the diameter of a collimated input beam to a larger collimated output beam. Beam expanders are used in applications such as laser scanning, laser cutting, interferometry, and remote sensing. The most common type of beam expander is derived from the Galilei telescope which usually has one negative input lens and one positive output lens, as shown in the following figure.
As shown in figure, the lens1 focuses the laser beam onto the front focuses plane and the new beam waist ω’_{0} and divergence angle θ’ can be represented as:
whereω(l) is the radius of the beam input the lens1, l is the distance between the lens1 and the beam waist ω_{0} , and f1 is the focal length of the lens1. Since ω’_{0}lies on the back focus plane of the lens2 with a longer focal length f2, the Gaussian beam with a beam ω’_{0}will be collimated by the beam expander. The collimation ratio of the beam expander for a Gaussian beam is as follows:
where T_{1} =f2/f1. The beam waist ω”_{0} and divergence angle θ” after the beam expander are:
Substituting Equation(1) to Equation(5), the following expression can be obtained:
From Equation(4)-(7), it is concluded the beam expansion ratio and the collimation ratio for a Gaussian beam depend not only on the specifications of the beam expander, but also on the laser beam parameters as well as the positions of the lenses.
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