Arbitrary polarization conversion using metasurfaces with angle-tunable-birefringence

June 5, 2020

angle_tunable_birefringence

In this work, we demonstrate a freeform metasurface with novel birefringent properties. Traditionally, birefringence is considered as an intrinsic material property and its behavior typically limited to what is known as linear birefringence. In this work, by using a photonic inverse design approach...

Multifunctional metasurfaces by dispersion engineering

May 23, 2020

Dispersion engineering

In this recently published work, we show that, by engineering the dispersion of each constituent nanostructure, a metalens can possess two different focal lengths with customized focal length shifts. The focal length shift can be designed with achromatic, refractive, or diffractive...

Visible metasurface-enhanced laser

April 28, 2020

Metasurface laser

In this work, we reveal a metasurface-enhanced laser that overcomes a key limitation in lasers: conjugate symmetry of light’s angular momentum. We demonstrate new high-purity orbital angular momentum (OAM) states with quantum numbers reaching 100 and non-symmetric vector vortex beams that...

Two Lasers in One

February 8, 2020

Two lasers

We demonstrated that a single semiconductor laser can produce both an amplitude-modulated and a frequency-modulated frequency comb, revealing a physical relationship between two types of output previously thought to be independent. The physics of the frequency combs is illustrated by an analogy with systems of...

All-glass, large-diameter metalens working at visible wavelengths made with conventional computer chip manufacturing methods

November 23, 2019

Large metalens

Metalenses are flat lenses that are ultrathin and lightweight, and are typically realized by placing millions to billions of nano-structures on a surface. The large number of structures makes scalability in both size and production scale a major concern. In our recent work, we demonstrate mass-...

Laughing gas laser: Widely tunable compact terahertz gas lasers with nitrous oxide

November 15, 2019

Laughing gas laser

We recently demonstrated a molecular gas laser that emits at frequencies between 250 GHz up to almost 1 THz using nitrous oxide (commonly known as laughing gas) as the gain medium. This laser relies on the optical pumping of the gas by a quantum cascade laser and can be generalized to a large number...

Capasso Group

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