Light recycling article for bio-assay

An optical well configured to receive a test sample for examining at least a first optical characteristic of the test sample at at least a first wavelength in a predetermined continuous wavelength range that is at least 150 nm wide and comprises at least a blue wavelength and a red wavelength, the optical well comprising:

• a wall comprising a bottom wall portion and a sidewall portion extending upwardly from the bottom wall portion, the bottom wall portion and the sidewall portion defining a chamber for receiving the test sample;
• and
• an integral and continuous thermoformed optical film formed into a shape so that at least a portion of the sidewall portion of the optical well comprises a first portion of the integral formed optical film and at least a portion of the bottom wall portion of the optical well comprises a different second portion of the integral formed optical film, the integral formed optical film comprising a plurality of microlayers numbering at least 10 in total, each of the microlayers having an average thickness of less than about 500 nm, such that for a normally incident light and for at least one polarization state, the plurality of microlayers in each of the first and second portions of the integral formed optical film has an average optical reflectance of greater than about 80% in the predetermined wavelength range,
• wherein, the forming results in the plurality of microlayers of the integral formed optical film having a thinnest portion and a thickest portion having a thickness difference of at least 30%.