A Plano Convex Cylindrical Lens is, in essence, a transparent cylinder with one flat surface and one extruding curved surface, which contributes to a positive focal length. The fundamental function of the plano-convex cylindrical lens is to condense a matrix of laser beams, when the matrix of laser beams needs to be focused inside a detector, the PCX cylindrical lens compresses the matrix into a single line. This trait also helps plano-convex cylindrical lenses to modulate the aspect ratio of the image. Just like its plate plano-convex lens cousin, a plano-convex cylindrical lens performs best at infinite absolute conjugate ratios, and becomes disadvantageous when the conjugate ratios are below 5:1. What discriminates a plate PCX and a cylindrical PCX are that the former diverges lights in two dimensions, the later expands light beam in one.
The prior nature of Plano-convex cylindrical lenses, which is making a two-dimensional light beam becomes a linear laser line, can be leveraged in diverse applications like the coupling of a slit input of laser diodes, changing the aspect ratio of an image, laser scanners, dye lasers, spectroscopies, and receivers of energies in linear detectors. A plano-convex lens can either modulate the aspect ratio of an image or create a line image from the point light beam source. A PCX cylindrical lens is also often hired to collect collimated light beams to generate a thin line.
Another crucial application of the Plano-convex cylindrical lens is anamorphic beam shaping, which just refers to correcting the elliptical-shaped laser beam generated from a laser diode into a circular-shaped one. The elliptical laser beam is the product of a rectangular Fresnel aperture and is undesirable because this implies a larger beam area which wastes more power, fewer homogeneities, and a terrible Gaussian Beam Profile. A pair of Plano-convex cylindrical lenses could be used to circularize the elliptical beams. During the test, a pair of plano-convex cylindrical lenses are positioned so that lenses are orthogonal as shown in the figure. From the result, we can conclude that using a pair of plano-convex cylindrical lenses to circularize the elliptical beam is a high-transmission, balance-shape, astigmatism-attenuated approach.
N-BK7 or its equivalent known as H-K9L is a ROHS-compliant borosilicate crown glass with superior optical excellence and the glass is fine annealed and polished to tight tolerances to meet the demanding tolerances. The most attractive advantages of N-BK7 are its high optical homogeneities and high transmission to VIS and NIR spectra. Besides, the hardness, chemical and thermal resilience of N-BK7 are also remarkable, it contains low levels of inclusions and bubbles, therefore N-BK7 is excellent for making high-precision optical lenses.
Hangzhou Shalom EO offers stocked N-BK7 Plano-Convex Cylindrical Lenses. The various focal lengths range from 4mm to 1000mm, while the dimensions also come in large selections to accommodate your requirements. Standard coating options include 350-650nm, 650-1050 nm, and 1050-1580nm anti-reflection coatings to elevate the transmission of the lens substrate, while uncoated and custom coating bandwidths could all be tailored through inquiries. With unceasing devotion and engineering intelligence, Shalom EO has earned credits among researchers and clients around the globe. Before shipment, the cylindrical lenses will undergo a stringent in-house inspection in our clean room using Zygo interferometers and other equipment to secure your interest.
Besides the off-the-shelf PCV cylindrical lens made from N-BK7, we also provide custom Plano-convex cylindrical lenses made from a wide portfolio of other materials including Fused Silica, CaF2, BaF2, MgF2, ZnSe, etc. With BBAR coatings, V-coatings, and cheaper MgF2 AR coatings.
Application Notes:
1. To minimize spherical aberration, engineers from Shalom EO suggest that incoming light beams should be projected to the curved side of the lens for diverging.
2. Diode Laser Shaping
A laser diode (a P-i-N diode), with electrical current flows between anodes cathodes on top of and below the semiconductor material substrate, in an intrinsic manner, leading to elliptical-shaped radiation of laser beam as if emitted from a rectangular aperture. An elliptical beam implies a either greater vertical or horizontal component. The two components can’t be equivalent. This is problematic because this decreases the irradiance, optical homogeneities, and beam qualities of the laser output, for instance, if the laser is utilized for pattern engraving, then elliptical beams will lower the working accuracies and efficiencies to a severe extent. The attenuation of input intensities, and aberrations to the Gaussian beam profile of lasers after circularization should all be taken into concerns.
A great measure to correct the situation is using a pair of plano-convex/concave cylindrical lenses. The cause of the elliptical beam shape is a rectangular aperture derived from Fresnel reflections. Now assume the angle between the optical axis and the vertical axis of the ellipse is θ1, and the angle between the optical axis and the horizontal axis of the ellipse is θ2 With the condition given, two cylindrical plano-convex/-concave lenses positioned and with focal lengths f2/f1 = θ1/θ2, can circularize the elliptical laser beam. In fact, the cylindrical lens pair provides a well-circularized beam, balanced circularization, and beam qualities with transmitted power. In addition to the compensation for much of the beam's astigmatism.
Figure 1. Circularization of an edge-emitting elliptical laser beam using a pair of plano-convex cylindrical lenses
3. Linear Condensation
Both plano concave cylindrical lenses and plano convex cylindrical lenses can realize spot-to-line magnification or beam-to-line condensation. E.g. a PCX cylindrical lens transforms a beam with an original diameter of a1 on the object side to a thin line on the image side according to a virtual focus, and the length of the line could be adjusted via changing the image distance.