Achieving 
/20 Resolution by One-Color Initiation and Deactivation of Polymerization
Linjie Li,1
Rafael R. Gattass,1
Erez Gershgoren,1
Hana Hwang,2
John T. Fourkas1,3,4,5,*
In conventional photolithography, diffraction limits the resolution
to about one-quarter of the wavelength of the light used. We
introduce an approach to photolithography in which multiphoton
absorption of pulsed 800-nanometer (nm) light is used to initiate
cross-linking in a polymer photoresist and one-photon absorption
of continuous-wave 800-nm light is used simultaneously to deactivate
the photopolymerization. By employing spatial phase-shaping
of the deactivation beam, we demonstrate the fabrication of
features with scalable resolution along the beam axis, down
to a 40-nm minimum feature size. We anticipate application of
this technique for the fabrication of diverse two- and three-dimensional
structures with a feature size that is a small fraction of the
wavelength of the light employed.
2 Department of Physics, University of Maryland, College Park, MD 20742, USA.
3 Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742, USA.
4 Maryland NanoCenter, University of Maryland, College Park, MD 20742, USA.
5 Center for Nanophysics and Advanced Materials, University of Maryland, College Park, MD 20742, USA.
* To whom correspondence should be addressed. E-mail: fourkas{at}umd.edu
