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Product Announcement

F-theta Lenses

16 Feb 2024

F-theta lenses are the optics of choice for laser scanning, engraving, and cutting systems. At Avantier we produce high-performing custom F-theta lenses for a wide range of clients.

An f-theta lens (also known as a plane field objective or scan lens) is not just one optical piece; it is an assembly containing three or four lenses pre-aligned and mounted within sturdy housing for easy use. While an ordinary lens can be used to focus a laser beam on a spherical surface, using an F-theta lens allows you to work with a plane-focusing surface. It also features a spot size that is almost constant over the scan field, and a laser spot position proportional to the scan angle. This makes it incredibly useful for use with lasers.

Key Parameters of an F-Theta Lens and Scanning System

When designing an F-theta lens for your application, key parameters to keep in mind are operating wavelength, spot size, and scan field diameter (SFD).

The operating wavelength is the wavelength of the laser that you’ll be working with. Spot size refers to the width of the laser beam. The scan field diameter  SFD or scan length of an F-theta lens is defined as the diagonal length of the square in which the beam can be focused by the lens.

Another important feature of a scanning system is the output scan angle, or OSA. This is the angle between the normal of the image plan and output laser beam (the beam after it has passed through the scan lens). For a tele centric lens the OSA will always be zero; otherwise, it will vary slightly across the image field.

Custom F-Theta Lenses at Avantier

Avantier specializes in custom F-theta lenses built to order for clients in industry, research, and medicine. Our optical engineers and designers have years of experience crafting high-performance optical components, and every piece that leaves our factory is carefully tested to meet the highest standards. Visit Avantier's custom F-Theta Lens page for more information.

Factory Standard

Lens Design

Compact design with 3 to 4 elements



Distortion (Max.)


Focal Length

Available from 63mm to 635mm

Custom Optical Coating

Working wavelength range from UV to visible to infrared

Lens Performance

Customized to fit specific application needs

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New Jersey
United States
Tel: 732-321-6915
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