A system for determining characteristics of an object or a sample, comprising: - at least a first and a second transmitter unit (11, 12), wherein the first transmitter unit is configured for transmitting first electromagnetic waves towards the object and the second transmitter unit is configured for transmitting second electromagnetic waves towards the object, wherein the first and/or the second transmitter unit (11, 12) is configured for generating terahertz waves; - at least one receiver unit for receiving electromagnetic waves from the object, the receiver unit generating a receiver signal upon receipt of the electromagnetic waves from the object, wherein - the first and the second transmitter unit (11, 12) is configured in such a way that the first and the second electromagnetic waves (T1, T2) are modulated differently in such a way that by demodulating the receiver signal, a portion of the receiver signal evoked by the first electromagnetic waves can be separated from a portion of the receiver signal evoked by the second electromagnetic waves, characterized by an evaluation unit configured for generating a two-dimensional and/or a three-dimensional reconstruction of the object using the receiver signal, wherein the first transmitter unit is configured in such a way that the first electromagnetic waves are modulated with a first modulation frequency and the second transmitter unit is configured in such a way the second electromagnetic waves are modulated with a second modulation frequency, the first modulation frequency being different from the second modulation frequency. - at least a first and a second transmitter unit (11, 12), wherein the first transmitter unit is configured for transmitting first electromagnetic waves towards the object and the second transmitter unit is configured for transmitting second electromagnetic waves towards the object, wherein the first and/or the second transmitter unit (11, 12) is configured for generating terahertz waves; - at least one receiver unit for receiving electromagnetic waves from the object, the receiver unit generating a receiver signal upon receipt of the electromagnetic waves from the object, wherein - the first and the second transmitter unit (11, 12) is configured in such a way that the first and the second electromagnetic waves (T1, T2) are modulated differently in such a way that by demodulating the receiver signal, a portion of the receiver signal evoked by the first electromagnetic waves can be separated from a portion of the receiver signal evoked by the second electromagnetic waves, characterized by an evaluation unit configured for generating a two-dimensional and/or a three-dimensional reconstruction of the object using the receiver signal, wherein the first transmitter unit is configured in such a way that the first electromagnetic waves are modulated with a first modulation frequency and the second transmitter unit is configured in such a way the second electromagnetic waves are modulated with a second modulation frequency, the first modulation frequency being different from the second modulation frequency. characterized by an evaluation unit configured for generating a two-dimensional and/or a three-dimensional reconstruction of the object using the receiver signal, wherein the first transmitter unit is configured in such a way that the first electromagnetic waves are modulated with a first modulation frequency and the second transmitter unit is configured in such a way the second electromagnetic waves are modulated with a second modulation frequency, the first modulation frequency being different from the second modulation frequency.