Methods and apparatus for fluorescence sensing employing fresnel zone plates

A multilayer apparatus comprising:

• a first layer comprising a first substrate;
• at least one Fresnel zone plate formed on the first substrate;
• a second layer comprising a second substrate;
• and
• at least one microfluidic channel formed on the second substrate;
• wherein
• the first and second layers are adapted to be placed in releasable contact with each other or a third layer to form a multilayer micro-optofluidic chip, and wherein, in the chip, the at least one Fresnel zone plate is configured to have a first focal region for excitation radiation, the first focal region substantially outside the at least one microfluidic channel, and a second focal region for fluorescent emission excited by the excitation radiation, the second focal region substantially within the at least one microfluidic channel.

An apparatus, comprising:

• an array of microfabricated optical elements;
• and
• a microfluidic drop generator configured to generate microfluidic drops,
• wherein the array of microfabricated optical elements and the microfluidic drop generator are integrated on a same chip.

A fluorescence sensing method, comprising:

• irradiating at least one microfabricated optical lens with excitation radiation, the at least one microfabricated optical lens being configured to focus the excitation radiation onto at least one microfluidic channel;
• providing a flow of at least one object in the at least one microfluidic channel, the at least one object generating a fluorescent emission when irradiated by the excitation radiation, at least a portion of the fluorescent emission passing through the at least one microfabricated optical lens;
• and
• relaying at least some of the portion of the fluorescent emission passing through the at least one microfabricated optical lens to a detecting location with a relay optic, the relay optic configured to exclude radiation emitted a selected distance from the at least one object generating the fluorescent emission.