Method and apparatus for determining the phase and/or amplitude information of an electromagnetic wave for photomixing

A method of determining the phase and/or amplitude information of an electromagnetic wave

• in which an electromagnetic wave is radiated onto the surface of a photonic mixing element having a plurality of pixels, wherein each of the pixels has at least two light-sensitive modulation photogates Gam and Gbm and associated accumulation gates Ga and Gb,
• in which there are applied to the modulation photogates Gam and Gbm modulation photogate voltages Uam(t) and Ubm(t) which are in the form of Uam(t)=Uo+Um(t) and Ubm(t)=Uo−Um(t), wherein Uo represents a bias voltage of the accumulation gates Ga and Gb,
• wherein applied to the accumulation gates Ga and Gb is a dc voltage whose magnitude is at least as great as the magnitude of the sum of Uo and the amplitude of the modulation voltage Um(t),
• in which charge carriers produced in a space charge zone of the modulation photogates Gam and Gbm by the electromagnetic wave are exposed to a potential gradient of a drift field in dependence on the polarity of the modulation photogate voltages Uam(t) and Ubm(t) and drift to the corresponding accumulation gate Ga and Gb,
• in which charges qa and qb which have drifted to the respective accumulation gates Ga and Gb are taken off, wherein a plurality of the pixels are arranged as a 3D-line or matrix camera, which is combined with a conventional 2D-camera, and
• wherein spectral allocation and feed of an active modulated illumination component to the 3D-camera and of other unmodulated illumination components is effected by a beam splitter.

A photonic mixing element

• with at least one pixel (1),
• which has at least two light-sensitive modulation photogates (Gam, Gbm) comprising terminals for and adapted to receive modulation photogate voltages Uam(t) and Ubm(t) which are in the form of Uam(t)=Uo+Um(t) and Ubm(t)=Uo−Um(t),
• accumulation gates (Ga, Gb) which are associated with the modulation photogates (Gam, Gbm) and which are shaded relative to an incident electromagnetic wave, wherein Uo represents a bias voltage of the accumulation gates (Ga, Gb) and Um(t) represents modulation voltage, and
• wherein an electronic pixel reading-out and signal pre-processing system is associated with a chip containing said pixel.

A 3D-camera comprising an apparatus for determining phase information of an electromagnetic wave, the apparatus

• having at least one photonic mixing element comprising:
• at least one pixel (1),
• which has at least two light-sensitive modulation photogates (Gam, Gbm) comprising terminals for and adapted to receive modulation photogate voltages Uam(t) and Ubm(t) which are in the form of Uam(t)=Uo+Um(t) and Ubm(t)=Uo−Um(t),
• accumulation gates (Ga, Gb) which are associated with the modulation photogates (Gam, Gbm) and which are shaded relative to an incident electromagnetic wave, wherein Uo represents a bias voltage of the accumulation gates Ga and Gb, and
• having a modulation generator (10, 13), and
• having a transmitter (4) that irradiates the electromagnetic wave which is intensity-modulated by the modulation generator (10, 13) in predetermined manner,
• wherein the electromagnetic wave which is reflected by an object (6) is radiated onto the surface of the photonic mixing element, and
• wherein the modulation generator (10, 13) supplies the photonic mixing element with modulation voltages Um(t) which are in a predetermined phase relationship with respect to the phase of the electromagnetic wave that is irradiated from the transmitter.

A method of determining the phase and/or amplitude information of an electromagnetic wave

• in which an electromagnetic wave is radiated onto the surface of a photonic mixing element having at least one pixel, wherein the pixel has at least two light-sensitive modulation photogates Gam and Gbm and associated accumulation gates Ga and Gb,
• in which there are applied to the modulation photogates Gam and Gbm modulation photogate voltages Uam(t) and Ubm(t) which are in the form of Uam(t)=Uo+Um(t) and Ubm(t)=Uo−Um(t), wherein Uo represents a bias voltage of the accumulation gates Ga and Gb,
• wherein applied to the accumulation gates Ga and Gb is a dc voltage whose magnitude is at least as great as the magnitude of the sum of Uo and the amplitude of the modulation voltage Um(t),
• in which charge carriers produced in a space charge zone of the modulation photogates Gam and Gbm by the electromagnetic wave are exposed to a potential gradient of a drift field in dependence on the polarity of the modulation photogate voltages Uam(t) and Ubm(t) and drift to the corresponding accumulation gate Ga and Gb,
• in which charges qa and qb which have drifted to the respective accumulation gates Ga and Gb are taken off, and
• wherein illumination of a scene is provided with modulated light from different spectral regions in order to obtain different color components of a resulting image for reconstructing a complete color image together with spatial depth information.