Versatile Implementation in Angle-Resolved Optical Microscopy: Its Application to Local Spectrometry of Microcavities with PIC-J-Aggregates

Versatile novel implementations in microspectroscopy are developed, which can provide angle-resolved optical spectroscopy at local sample areas almost in diffraction limit. By selecting focus position of light flux incident within the back focal plane of the objective lens radially from the position of the optical axis of the microscope with employing off-centered pinhole, we can obtain parallel beam with oblique incidence and its angle tuning at the sample surface. In this paper, we describe our specific optical setup and its practical working principle in detail. We report, as a demonstration of its performance, our latest studies on optical properties of cavity polariton states in the so-called quantum microcavity structures, which contain molecular J-aggregates of pseudoisocyanine (PIC) dye as active working materials. By using the microscope technique, we obtain a fair amount of improvement in the linewidth observation of cavity polariton spectra. 1. Introduction With spectacular development of recent microfabrication technologies, it is increasingly important to monitor optical properties of matters at its more minute levels. As a result, the studies with microspectroscopy, the combination of traditional optical microscope and spectroscopic measurement, have been widely conducted. One of the most significant and informative spectroscopic techniques is the observation of the angle-resolved optical features. Nevertheless, implementations for such microspectroscopes have never been reported within our knowledge. Here we have developed novel optical microscopy system which can provide observations on the angular-dependent optical features at local sample regions almost to its diffraction-limited spatial resolution. This system should possess broader utilities and work in a wide variety of situations, for example, fundamental studies such as local optical spectra of materials with specifically fabricated structures, evaluations of microfabricated photonic as well as electronic functional devices. In this paper, specific optical microscope system with incident-angle-tunable Koehler type illumination is reported and its practical working principle as well. In addition, we introduce part of our latest studies about reflectance spectrometric measurement of molecular J-aggregates consist of pseudoisocyanine (PIC; 1,1′-diethyl-2,2′-cyanine chloride) dye in metal-mirror microcavity structures, as an example of the application of such system. The microcavities containing J-aggregates are known as the useful structures to form strong-coupling states between