Lenses form the basic building blocks of many common optical devices, including cameras, binoculars, microscopes, and telescopes. They are essential light-controlling elements, used primarily for light gathering and image formation. Both lenses and curved mirrors can achieve similar outcomes in terms of light collection and image formation. However, lenses often provide superior image quality due to their transparency, which allows light to pass directly along the axis to the detector. Mirrors, on the other hand, generally require an off-axis geometry and are typically preferred for light collection because they can be made lighter and larger than lenses.
Lense is the most basic optical component, It collects light from a source and refracts that light to form a usable image of the source. Lenses have many applications, ranging from the simple collection of the scanning of laser beams to precise imaging and image transfer.
Refraction and Snell’s Law
Refraction is the phenomenon where light changes its angle when it passes from one medium to another. This change in direction occurs because light’s speed varies between different media, being inversely proportional to the medium’s index of refraction. Snell’s law governs how lenses control light transmission for collection and imaging.
Minimizing Aberrations
- Plano-Convex Lenses: Best for focusing parallel rays to a single point.
Plano-Convex lenses are the best choice for focusing parallel rays of light to a single point. Our plano-convex lenses are fabricated from N-BK7, UV fused silica, N-SF11,Germanium,Silicon etc
- Bi-Convex Lenses: Ideal for imaging when the object and image are at similar distances from the lens.
A biconvex lens, also known as a double convex lens, is a type of lens that is thicker in the middle and thinner at the edges, with both surfaces curved outwardly. Our biconvex lenses are fabricated from N-BK7, UV fused silica, N-SF11,Germanium,Silicon etc.
- Aspheric Lenses: Have tailored curvatures to minimize aberrations but are more expensive to manufacture.
Aspherical lenses are available molded, CNC-polished,either with or without anti-reflection (AR) coatings. Aspheres are often employed to collimate light exiting a fiber or laser diode. The surface of an asphere is designed to eliminate spherical aberration.
- Achromatic Doublets: Minimize chromatic aberrations by using two lenses with different dispersions to produce a focal length independent of wavelength.
An achromatic lens, also known as a doublet lens, is a type of lens designed to reduce chromatic aberration. It is a lens consisting of two cemented elements made of different materials. Chromatic aberration is a phenomenon in optics where different colors of light are focused at different distances, causing color fringes and blurring in images. The achromate lense offers superior correction of spherical aberration in monochromatic applicaitons.
- Microscope Objectives: Multi-element systems that significantly reduce aberrations but are complex and costly.
Special Lens Types
- Cylindrical Lenses: Focus or expand light in one axis only, ideal for modifying asymmetric beams, such as those from laser diodes.
Considerations for Choosing Lenses
When selecting a lens, several features need to be considered:
- Focal Length: Determines the distance over which the lens can focus light.
- Lens Shape: Affects the focusing ability and introduction of aberrations.
- Lens Material: Impacts the transmission properties and suitability for different applications.
- Transmission Properties: The ability of the lens to transmit light efficiently.
- Wavefront Distortion: Affects image quality by introducing deviations in the light path.
- Scattered Light: Can degrade image quality.
- Coatings: Anti-reflective coatings can enhance transmission and reduce unwanted reflections.
- Cost: Varies depending on the complexity of design and materials used.
By understanding these factors, one can select the appropriate lens to achieve the desired optical performance for specific applications.
Contact Us
Our design team at MOK Optics Co., Ltd. is ready to collaborate on custom lenses and other optical systems tailored to your specific application needs. For more information, please contact us for a detailed consultation and quote.
Email: info@mokoptics.com
Phone: +86-180-6070-8760