Quantum lithography is a type of
photolithography
In integrated circuit manufacturing, photolithography or optical lithography is a general term used for techniques that use light to produce minutely patterned thin films of suitable materials over a substrate, such as a silicon wafer (electroni ...
, which exploits non-classical properties of the photons, such as
quantum entanglement
Quantum entanglement is the phenomenon that occurs when a group of particles are generated, interact, or share spatial proximity in a way such that the quantum state of each particle of the group cannot be described independently of the state o ...
, in order to achieve superior performance over ordinary classical lithography. Quantum lithography is closely related to the fields of
quantum imaging Quantum imaging is a new sub-field of quantum optics that exploits quantum correlations such as quantum entanglement of the electromagnetic field in order to image objects with a resolution or other imaging criteria that is beyond what is possible i ...
,
quantum metrology
Quantum metrology is the study of making high-resolution and highly sensitive measurements of physical parameters using quantum theory to describe the physical systems, particularly exploiting quantum entanglement and quantum squeezing. This fie ...
, and
quantum sensing
A quantum sensor utilizes properties of quantum mechanics, such as quantum entanglement, quantum interference, and quantum state squeezing, which have optimized precision and beat current limits in sensor technology.
The field of quantum sensi ...
. The effect exploits the quantum mechanical state of light called the
NOON state
In quantum optics, a NOON state or N00N state is a quantum-mechanical many-body entangled state:
: , \psi_\text \rangle = \frac, \,
which represents a superposition of ''N'' particles in mode ''a'' with zero particles in mode ''b'', and vice ...
. Quantum lithography was invented at
Jonathan P. Dowling
Jonathan P. Dowling (3 April 1955 – 5 June 2020) was an Irish-American researcher and professor in theoretical physics, known for his work on quantum technology, particularly for exploiting quantum entanglement (in the form of a NOON state) f ...
's group at
JPL
The Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center in the City of La Cañada Flintridge, California, United States.
Founded in the 1930s by Caltech researchers, JPL is owned by NASA a ...
, and has been studied by a number of groups.
Of particular importance, quantum lithography can beat the classical
Rayleigh criterion
Angular resolution describes the ability of any image-forming device such as an optical or radio telescope, a microscope, a camera, or an eye, to distinguish small details of an object, thereby making it a major determinant of image resolution ...
for the
diffraction limit. Classical
photolithography
In integrated circuit manufacturing, photolithography or optical lithography is a general term used for techniques that use light to produce minutely patterned thin films of suitable materials over a substrate, such as a silicon wafer (electroni ...
has an
optical imaging Medical optical imaging is the use of light as an investigational imaging technique for medical applications. Examples include optical microscopy, spectroscopy, endoscopy, scanning laser ophthalmoscopy, laser Doppler imaging, and optical coherence t ...
resolution that cannot be smaller than the wavelength of light used. For example, in the use of
photolithography
In integrated circuit manufacturing, photolithography or optical lithography is a general term used for techniques that use light to produce minutely patterned thin films of suitable materials over a substrate, such as a silicon wafer (electroni ...
to mass-produce computer chips, it is desirable to produce smaller and smaller features on the chip, which classically requires moving to smaller and smaller wavelengths (ultraviolet and x-ray), which entails exponentially greater cost to produce the optical imaging systems at these extremely short optical wavelengths.
Quantum lithography exploits the
quantum entanglement
Quantum entanglement is the phenomenon that occurs when a group of particles are generated, interact, or share spatial proximity in a way such that the quantum state of each particle of the group cannot be described independently of the state o ...
between specially prepared photons in the
NOON state
In quantum optics, a NOON state or N00N state is a quantum-mechanical many-body entangled state:
: , \psi_\text \rangle = \frac, \,
which represents a superposition of ''N'' particles in mode ''a'' with zero particles in mode ''b'', and vice ...
and special
photoresist
A photoresist (also known simply as a resist) is a light-sensitive material used in several processes, such as photolithography and photoengraving, to form a patterned coating on a surface. This process is crucial in the electronic industry.
...
s, that display multi-photon absorption processes to achieve the smaller resolution without the requirement of shorter wavelengths. For example, a beam of red photons, entangled 50 at a time in the NOON state, would have the same resolving power as a beam of x-ray photons.
The field of quantum lithography is in its infancy, and although experimental proofs of principle have been carried out using the
Hong–Ou–Mandel effect
The Hong–Ou–Mandel effect is a two-photon interference effect in quantum optics that was demonstrated in 1987 by three physicists from the University of Rochester: Chung Ki Hong (홍정기), Zheyu Ou (区泽宇), and Leonard Mandel.
The ef ...
,
it is still a long way from practical uses.
References
{{reflist
External links
American Institute of PhysicsIntroduction to Quantum LithographyScience News
Quantum information science
Lithography (microfabrication)