Lasse Karvonen

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Black phosphorus (BP) has recently been rediscovered as a new and interesting two-dimensional material due to its unique electronic and optical properties. Here, we study the linear and nonlinear optical properties of BP flakes. We observe that both the linear and nonlinear optical properties are anisotropic and can be tuned by the film thickness in BP,(More)
Gallium selenide (GaSe) is a layered semiconductor and a well-known nonlinear optical crystal. The discovery of graphene has created a new vast research field focusing on two-dimensional materials. We report on the nonlinear optical properties of few-layer GaSe using multiphoton microscopy. Both second- and third-harmonic generation from few-layer GaSe(More)
Silk fibers are expected to become a pathway to biocompatible and bioresorbable waveguides, which could be used to deliver localized optical power for various applications, e.g., optical therapy or imaging inside living tissue. Here, for the first time, the linear and nonlinear optical properties of natural silk fibers have been studied. The waveguiding(More)
Carbon is the most well-known black material in the history of man. Throughout the centuries, carbon has been used as a black material for paintings, camouflage, and optics. Although, the techniques to make other black surfaces have evolved and become more sophisticated with time, carbon still remains one of the best black materials. Another well-known(More)
Silver nanoparticles embedded in glass are prepared by double ion-exchange process. Silver ions are introduced into glass in silver ion-exchange, and reduced into metallic silver in subsequent potassium ion-exchange. The formed particles are characterized by optical absorption measurement and transmission electron microscopy, and their application in SERS(More)
The cellular mechanism responsible for the death of cerebellar granule neurons in the weaver mutant mouse is still being intensely investigated. To determine if alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) glutamate receptors are involved in producing the weaver phenotype or are altered by the weaver gene, we used (1) reverse(More)
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