A solid immersion lens (SIL) has higher

magnification Magnification is the process of enlarging the apparent size, not physical size, of something. This enlargement is quantified by a size ratio called optical magnification. When this number is less than one, it refers to a reduction in size, so ...

and higher

numerical aperture In optics, the numerical aperture (NA) of an optical system is a dimensionless number that characterizes the range of angles over which the system can accept or emit light. By incorporating index of refraction in its definition, has the property ...

than common

lenses A lens is a transmissive optical device that focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements''), ...

by filling the object space with a high- refractive-index solid material. SIL was originally developed for enhancing the

spatial resolution In physics and geosciences, the term spatial resolution refers to distance between independent measurements, or the physical dimension that represents a pixel of the image. While in some instruments, like cameras and telescopes, spatial resoluti ...

optical microscopy Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultravio ...

. There are two types of SIL: * Hemispherical SIL: Theoretically capable of increasing the numerical aperture of an optical system by

n

, the index of refraction of the material of the lens. * Weierstrass SIL (''superhemispherical SIL'' or ''superSIL''): the height of the truncated sphere is

(1+1/n)r

, where r is the radius of the spherical surface of the lens. Theoretically capable of increasing the numerical aperture of an optical system by

n^2

Applications of SIL

Solid immersion lens microscopy

All optical microscopes are

diffraction-limited In optics, any optical instrument or systema microscope, telescope, or camerahas a principal limit to its resolution due to the physics of diffraction. An optical instrument is said to be diffraction-limited if it has reached this limit of res ...

because of the wave nature of light. Current research focuses on techniques to go beyond this limit known as the

Rayleigh criterion Rayleigh criterion may refer to: * , optical angular resolution * , instability criterion in Taylor–Couette flow * Rayleigh roughness criterion, surface roughness criterion in optics * Rayleigh criterion (thermo-acoustic instability), criterion ...

. The use of SIL can achieve spatial resolution better than the diffraction limit in air, for both

far-field The near field and far field are regions of the electromagnetic (EM) field around an object, such as a transmitting antenna, or the result of radiation scattering off an object. Non-radiative ''near-field'' behaviors dominate close to the an ...

imaging L. Hu, R. Chen, K. Agarwal, C. Sheppard, J. Phang, and X. Chen, "Dyadic Green’s function for aplanatic solid immersion lens based sub-surface microscopy," Opt. Express 19, 19280-19295 (2011). and near-field imaging.

Optical data storage

Because SIL provides high spatial resolution, the spot size of

laser A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word ''laser'' originated as an acronym for light amplification by stimulated emission of radi ...

beam through the SIL can be smaller than diffraction limit in air, and the density of the associated optical data storage can be increased.

Photolithography

Similar to

immersion lithography Immersion lithography is a technique used in semiconductor manufacturing to enhance the resolution and accuracy of the lithographic process. It involves using a liquid medium, typically water, between the lens and the wafer during exposure. By ...

, the use of SIL can increase spatial resolution of projected

photolithographic Photolithography (also known as optical lithography) is a process used in the manufacturing of integrated circuits. It involves using light to transfer a pattern onto a substrate, typically a silicon wafer. The process begins with a photosensit ...

patterns, creating smaller components on

wafers A wafer is a crisp, often sweet, very thin, flat, light biscuit, often used to decorate ice cream, and also used as a garnish on some sweet dishes. They frequently have a waffle surface pattern but may also be patterned with insignia of the foo ...

. Emission Microscopy Offers advantages for semiconductor wafer emission microscopy which detects faint emissions of light (Photons) from electron-hole recombination under the influence of electrical stimulation.{{citation needed, date=October 2022

References

Microscope components Lenses Heat-assisted magnetic recording