Molecules as Sources for Indistinguishable Single Photons

We report on the triggered generation of indistinguishable photons by solid-state single-photon sources in two separate cryogenic laser scanning microscopes. Organic fluorescent molecules were used as emitters and investigated by means of high resolution laser spectroscopy. Continuous-wave photon correlation measurements on individual molecules proved the isolation of single quantum systems. By using frequency selective pulsed excitation of the molecule and efficient spectral filtering of its emission, we produced triggered Fourier-limited single photons. In a further step, local electric fields were applied to match the emission wavelengths of two different molecules via Stark effect. Identical single photons are indispensible for the realization of various quantum information processing schemes proposed. The solid-state approach presented here prepares the way towards the integration of multiple bright sources of single photons on a single chip.Comment: Accepted for publication in J. Mod. Opt. This is the original submitted versio

Realization of two Fourier-limited solid-state single-photon sources

We demonstrate two solid-state sources of indistinguishable single photons. High resolution laser spectroscopy and optical microscopy were combined at T = 1.4 K to identify individual molecules in two independent microscopes. The Stark effect was exploited to shift the transition frequency of a given molecule and thus obtain single photon sources with perfect spectral overlap. Our experimental arrangement sets the ground for the realization of various quantum interference and information processing experiments.Comment: 6 page

Pupils' Drawings as a Research Tool in Mathematical Problem-Solving Lessons

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Opettajan toiminnan yhteys kolmasluokkalaisten onnistumiseen ongelmatehtävän ratkaisemisessa

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Collective emotional atmosphere in mathematics lesson based on finnish fifth graders’ drawings

The aim of this study, based on pupils’ drawings, is to find out what kind of collective emotional atmosphere dominates in fifth-graders’ mathematics lessons. Pupils’ (N = 136) drawings were analyzed using a holistic evaluation of emotional atmosphere during mathematics lesson. Even though the collective emotional atmosphere in mathematics lesson is positive in the total data, there are large differences among the different classrooms. In most of the classrooms the emotional atmosphere could be described more or less as ambivalent (there are both positive and negative facial or other expressions). In two classrooms the emotional atmosphere could be described as positive and only in one as neutral. The differences between the classrooms are thus large. Based on our data, it can be said that asking pupils to do drawings is a good and many-sided method to collect data about the collective emotional atmosphere of a teaching group.Peer reviewe

Teachers' and fourth graders' questions during a problem-solving lesson

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Emotional atmosphere in third-graders’ mathematics classroom – an analysis of pupils’ drawings

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Opettajien ja oppilaiden kysymykset ongelmanratkaisutunnilla

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Tunneilmapiiri kolmasluokkalaisten matematiikkapiirroksissa

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Tutkimusprojekti Suomi–Chile alakoulun matematiikan opetuksessa

Non peer reviewe