Functional nonlinear spectroscopy
K. J. Karki, "Increasing the density of modes in an optical frequency comb by cascaded four-wave mixing in a nonlinear optical fiber", Phys. Rev. A 96, 043802 (2017).
S. Ghosh, S. K. Pal, K. J. Karki, T. Pullerits, "Ion migration heals trapping centers in CH3NH3PbBr3 perovskite", ACS Energy Lett. 2, 2133-2139 (2017).
V. Al. Osipov, X. Shang, T. Hansen, T. Pullerits, K. J. Karki, "Nature of relaxation processes revealed by the action signals of intensity-modulated light fields", Phys. Rev. A 94, 053845 (2016).
K. J. Karki, M. Abdellah, W. Zhang, T. Pullerits, "Different emissive states in the bulk and at the surface of methylammonium lead bromide perovskite revealed by two-photon micro-spectroscopy and lifetime measurements", Appl. Phys. Lett. Photonics 1, 046103 (2016).
K. J. Karki, L. Kringle, A. H. Marcus, T. Pullerits, "Phase-synchronous detection of coherent and incoherent nonlinear signals", J. Opt. 18, 015504 (2015).
K. J. Karki, J. R. Widom, J. Seibt, I. Moody, M. C. Lonergan, T. Pullerits, A. H. Marcus, "Coherent two-dimensional photocurrent spectroscopy in a PbS quantum dot photocell", Nat. Commun. 5, 5869 (2014).
S. Fu, A. Sakurai, L. Liu, F. Edman, T. Pullerits, V. Öwall, K. J. Karki, "Generalized lock-in amplifier for precision measurement of high frequency signals", Rev. Sci. Instrum 84, 115101 (2013).