If we analysis a sample using two different spectroscopic techniques (atomic emission spectroscopy and atomic absorption spectroscopy) both spectrum will be similar or different?
AAS and AES are opposite phenomena. AAS works by the adsorption of wavelengths of optical light electromagnetic radiation resulting in electrons jumping from one energy state to a higher excited energy state; whereas AES works by the emitting of wavelengths of electromagnetic as a result of excited electrons dropping from one excited energy state to a lower energy state. As a visual comparison the following link is more of an illustration I like about AAS and AES: https://image1.slideserve.com/2707921/atomic-emission-n.jpg
So you ask will the AAS and AES be similar or different? Complimentary and similar but not the same as they are opposite phenomena. To say different sounds like the wrong word to be thinking of; different/complimentary as they are opposite phenomena.
Laser induced breakdown spectroscopy is an emission spectroscopy (Pratik M. Tailor has written it opposite). Emission spectroscopy is opposite in nature with absorption spectroscopy. However the wavelength involved in transition remains the same.