A delay circuit that includes a plurality of delay cells connected in series. The method can be used to remove undesirable compounds from tobacco, tobacco materials, or tobacco smoke. In some embodiments, the aspect ratios of the one or more other portions are about 15:1 or less, or about 7:1 or less, and have a cylindrical or conical cross-sectional shape. The condensing lens is positioned in the housing, which is configured for converging the light incident thereon.